In the late 90s and early 2000s, software development was a labyrinth of incompatible languages and disjointed platforms, leaving developers in a perpetual struggle to weave together cohesive applications. This fragmentation and complexity called for a new approach — a single, unified framework that could bridge the divide. Enter .NET. 

.NET was created by Microsoft in the late 1990s, primarily as a direct competitor to Java. Upon its release in 2002, .NET addressed a critical challenge faced by developers: the need for a unified framework that could support the development of applications across various platforms. Initially Windows-centric, .NET has since evolved into a free, open-source, cross-platform framework that seamlessly supports a myriad of applications, including those for cloud, web, desktop, mobile, gaming, IoT, and AI. The versatility of .NET, coupled with its ability to cater to small-scale web development projects as well as large, complex enterprise-level applications, further solidifies its position as a go-to framework in software development.

Despite being decades old, .NET continues to be one of the most sought-after skills in today’s tech job market, ranking 11th in the list of most in-demand technical skills according to HackerRank’s 2023 Developer Skills Report. In the sections that follow, we’ll dive deeper into the intricacies of .NET, exploring its key features, components, use cases, and the essential skills required to work with this framework.

Understanding .NET

One of the core strengths of .NET is its ability to run on different platforms, including Windows, macOS, and Linux. This cross-platform functionality is facilitated by .NET Core, a key component of the .NET ecosystem. .NET Core is designed to be lightweight and modular, providing developers with the flexibility to include only the necessary parts for their applications, thus making the development process more streamlined and efficient.

ASP.NET, another vital part of the .NET ecosystem, is a framework specifically tailored for web development. It enables developers to create dynamic web pages, applications, and services, leveraging a model-view-controller (MVC) architecture that separates the application logic from the user interface. This separation simplifies the development process and allows for more manageable codebases.

Xamarin is a .NET framework dedicated to mobile application development. It provides tools and libraries that enable developers to create applications that can run on both Android and iOS devices, significantly reducing the time and resources required to develop cross-platform mobile apps.

In addition to these frameworks, the .NET ecosystem encompasses a variety of other tools and libraries, such as Entity Framework for data access and ML.NET for machine learning applications. Each of these components plays a crucial role in simplifying the development process and providing developers with the tools they need to bring their innovative ideas to life.

Key Features and Components of .NET

.NET is enriched with a host of features and components that together create a powerful and versatile development environment. Let’s delve into some of the key features and components that make up the .NET framework.

Common Language Runtime (CLR)

The CLR is the execution engine that handles running applications. It provides services such as memory management, security, and exception handling, thereby streamlining application development and reducing the complexity associated with these tasks.

Framework Class Library (FCL)

The FCL is a comprehensive collection of reusable classes, interfaces, and value types that are crucial to .NET applications. It provides functionalities that can be used across different .NET applications, including file input/output, data access, serialization, and more, thus facilitating code reuse and efficiency.

Language Interoperability

One of .NET’s significant advantages is its support for multiple programming languages, allowing developers to choose the language that best suits their needs. Language interoperability refers to the ability of code written in one language to interact seamlessly with code written in another, providing developers with the flexibility to leverage the strengths of different languages within a single application.

Base Class Library (BCL)

The BCL is a subset of the FCL and provides classes that are fundamental to .NET applications. It includes classes for basic functionalities such as strings, dates, and numbers, as well as more complex operations like file I/O, threading, and security.

Managed Code

Managed code is code that is executed by the CLR rather than the operating system. The CLR provides services like garbage collection, type checking, and exception handling to managed code, thereby enhancing its performance and security.

Understanding these key features and components is vital for anyone looking to work with or hire for .NET development. They form the building blocks of the .NET framework and are essential to creating efficient, scalable, and high-performance applications.

Why Teams Choose .NET

There’s no shortage of development frameworks to choose from, so what makes .NET stand out?

Versatility

.NET supports a range of application types, from web and mobile to desktop and cloud-based solutions. This versatility means that teams can use .NET for a multitude of projects, providing a consistent development environment across different application types.

Language Support

With support for multiple programming languages including C#, F#, and Visual Basic, .NET offers developers the flexibility to choose the language that best suits their needs. This language interoperability also makes it easier to integrate with existing systems or to leverage existing codebases.

Rich Ecosystem

The .NET ecosystem is vast, with a wealth of libraries, frameworks, and tools available to developers. This rich ecosystem means that teams can find the tools they need to solve almost any problem, from data access with Entity Framework to machine learning with ML.NET.

Community and Documentation

.NET has a large and active community of developers who contribute to the framework, provide support through forums and social media, and develop third-party tools and libraries. In addition, Microsoft offers extensive documentation and learning resources, making it easier for teams to adopt and master the framework.

Cross-Platform Development

With the introduction of .NET Core, developers can now build applications that run on Windows, macOS, and Linux. This cross-platform capability is a major draw for teams that need to support multiple operating systems.

Performance

.NET is known for its performance, with a just-in-time compiler, automatic memory management, and other features that optimize application speed and efficiency. This performance advantage can be a significant factor for teams working on high-performance applications.

Security

Security is a top priority in .NET, with features such as cryptographic services, role-based security, and the ability to create secure, isolated environments for application execution. These security features provide peace of mind for teams working on sensitive or high-stakes projects.

Key Skills Needed to Work with the .NET Ecosystem

Working with the .NET platform requires a range of technical and non-technical skills. Here are some of the key skills that are crucial for any .NET developer:

• Programming Languages
  • Proficiency in C# is essential, as it is the most commonly used language in the .NET ecosystem.
  • Knowledge of F# or Visual Basic can be beneficial, depending on the specific needs of the project.

• ASP.NET MVC
  • Understanding the model-view-controller (MVC) architecture is crucial for developing web applications using ASP.NET.
  • Familiarity with Razor syntax and .NET Core can also be beneficial.

• Entity Framework
  • Experience with Entity Framework or another object-relational mapping (ORM) tool is important for handling data access in .NET applications.

• Front-End Technologies
  • While .NET is primarily a back-end framework, developers should also have a strong grasp of front-end technologies like HTML, CSS, and JavaScript.
  • Knowledge of front-end frameworks like Angular, React, or Vue.js can be a plus.
• Cloud Platforms
  • Understanding cloud platforms, particularly Microsoft Azure, is becoming increasingly important as more applications move to the cloud.
• Testing
  • Proficiency in testing methodologies and tools, such as NUnit or xUnit, is important for ensuring the quality and reliability of .NET applications.
• Agile Methodologies
  • Experience with agile development methodologies, such as Scrum or Kanban, is beneficial, as many teams operate in an agile environment.
• Soft Skills
  • Strong communication and collaboration skills are important for working effectively in a team.
  • Problem-solving skills and a keen attention to detail are also crucial for a .NET developer.

By mastering these skills, developers can maximize their potential within the .NET ecosystem, contributing to successful projects and advancing their careers. Employers should look for these skills when hiring .NET developers, as they are indicative of a candidate’s ability to effectively work with the .NET platform.

The Future of .NET in Software Development

.NET is positioned to remain a cornerstone in the world of software development. With its robust set of features, extensive library support, and the backing of a thriving community, .NET is well-equipped to adapt and thrive in the evolving needs of tech teams. The continual enhancements and updates from Microsoft ensure that .NET remains relevant and capable of meeting the demands of modern software development. 

Furthermore, the growth of cloud computing and the Internet of Things (IoT) presents new opportunities for .NET developers. With .NET’s support for cloud platforms, particularly Microsoft Azure, and its compatibility with IoT devices, developers can leverage the framework to build innovative and sophisticated cloud-based solutions and IoT applications. The integration of artificial intelligence and machine learning into .NET also opens up endless possibilities.

For companies looking to stay ahead of the curve, investing in .NET training and encouraging a culture of continuous learning is key. As the capabilities of .NET expand, teams equipped with the necessary skills will be well positioned to leverage this tool to its full potential, ultimately driving innovation and success.

This article was written with the help of AI. Can you tell which parts?

The post What is .NET? Unpacking Microsoft’s Versatile Platform appeared first on HackerRank Blog.

When it comes to building robust and versatile software applications, the programming language you choose can significantly influence the project’s outcome. Among the plethora of programming languages that developers have at their disposal, one that often captures attention is C#. With its powerful features, wide range of use cases, and strong backing from Microsoft, C# continues to be a crucial player in the programming world.

In fact, despite its release more than 20 years ago, C# remains a top choice for developers. In our 2023 Developer Skills Report, it ranked fifth in the list of most preferred programming languages, moving up a spot from 2022 to overtake SQL. 

Given its wide-ranging applications and enduring popularity, C# has secured its place on the list of languages worth mastering — not only for programmers aiming to work within Microsoft’s ecosystem of technologies and platforms but also for those looking to build a broad variety of applications across different platforms and industries. In this post, we’ll explore exactly why, pulling back the curtain on C# and diving into its key features, applications, and the exciting opportunities available to both the developers and businesses leveraging this battle-tested language. 

What is C#?

C# — pronounced “C Sharp” — is a modern, general-purpose, object-oriented programming language developed by Microsoft as part of its .NET initiative and later approved as a standard by the European Computer Manufacturers Association (ECMA) and the International Standards Organization (ISO). Introduced in 2000, C# was designed by Anders Hejlsberg, a distinguished engineer at Microsoft, who aimed to create a language that combined the computing power of C++ with the simplicity and productivity of Visual Basic.

At the heart of C# lies a clear and type-safe object-oriented programming model, making it a favorite among developers for a wide array of applications. C# syntax is highly expressive, yet it’s also simple and easy to learn. The curly-brace syntax of C# will be instantly recognizable to anyone familiar with C, C++, or Java. This accessibility means that developers new to the language can become productive quickly.

But C# is more than just a simple language. It incorporates key concepts from several other programming paradigms, including component-oriented, functional, and generic programming models. These help to make C# a versatile and flexible language, capable of tackling a wide range of problems and tasks.

​​Key Features and Advantages of C#

C# comes packed with several unique features and advantages that make it a language of choice for many software development projects. Let’s explore some of the notable characteristics that set C# apart.

• Strongly- and Statically-Typed Language: C# is a statically-typed language, meaning that types are checked at compile time. This feature, combined with powerful tools in Visual Studio, helps developers catch errors early in the development process, enhancing code quality and maintainability.
• Object-Oriented Programming (OOP): C# is fundamentally object oriented, supporting key OOP concepts such as inheritance, encapsulation, polymorphism, and abstraction. This makes it ideal for building large-scale applications and promotes clean, modular code.
• Integrated Development Environment (IDE) Support: C# benefits from robust tooling support, particularly from Visual Studio, Microsoft’s flagship IDE. With features like IntelliSense for code completion, advanced debugging tools, and built-in support for testing and version control, Visual Studio significantly enhances developer productivity.
• Cross-Platform Development: With the introduction of .NET Core, a cross-platform, open-source version of .NET, C# can now be used to build applications that run on a variety of platforms, including Windows, macOS, and Linux. This has greatly expanded the potential use cases for C#.
• Comprehensive Libraries and Frameworks: C# has a rich set of libraries and frameworks, such as .NET Framework and .NET Core, which offer pre-written code to handle common programming tasks. This reduces the amount of code developers have to write and makes them more productive.
• Interoperability: C# has the ability to interact with many other languages and technologies, notably through COM Interop and P/Invoke, which allow C# programs to use components and APIs written in other languages.
• Automatic Garbage Collection: C# manages memory automatically with its garbage collector, which frees up memory by destroying objects that are no longer in use. This helps to prevent common programming errors and memory leaks.
• Language-Integrated Query (LINQ): LINQ is a unique feature in C# that allows developers to query data from a variety of sources in a type-safe manner directly from the language itself, rather than having to rely on separate query languages.

These features and many more make C# a versatile, efficient, and powerful programming language that is up to the task of handling a wide range of software development projects. Now, let’s take a closer look at the practical applications of C# in various domains.

Practical Use Cases of C#

Windows Desktop Applications: Since its creation, C# has been used extensively to build Windows desktop applications. Its integration with the .NET Framework provides a huge set of libraries and tools that make it easier to develop powerful Windows applications. Examples include professional-grade software like Microsoft Office and popular PC games using the Unity game engine.

Web Development: C# is a popular choice for building dynamic and robust web applications and services, with the ASP.NET framework being the tool of choice for many developers. ASP.NET allows for the creation of everything from small personal websites to large, enterprise-level web applications.

Game Development: C# has become a leading language in game development, thanks to the Unity game development engine. Unity’s use of C# allows developers to create multi-platform games with complex graphics, physics, and interactive gameplay. Many successful PC, console, and mobile games have been built using Unity and C#.

Mobile Applications: With frameworks like Xamarin — which is now integrated directly into .NET — C# developers can use their existing skills and codebase to build cross-platform mobile applications. Xamarin enables developers to create apps for Android, iOS, and Windows that share a common C# codebase but can still access native platform features.

Enterprise Applications: Many large corporations use C# to build their internal applications or back-end services. Its strong type checking, advanced debugging facilities, and integration with Microsoft’s SQL Server database technology make C# an excellent choice for creating reliable, scalable enterprise software.

Cloud-Based Applications: With the rise of cloud computing, C# has become a popular choice for building cloud-based applications. Microsoft’s Azure platform provides extensive support for C#, making it easy to create, deploy, and scale cloud applications.

Internet of Things (IoT) Applications: C# can also be used to develop IoT applications, thanks to frameworks like the Windows 10 IoT Core and libraries for working with specific devices. These tools allow developers to use C# to control and interact with a wide range of IoT devices.

The diverse range of use cases for C# illustrates the language’s flexibility and wide-ranging capabilities. Now, let’s explore what the job market looks like for those with C# skills.

High Demand for C# Skills in the Job Market

The demand for proficient C# programmers has remained consistently strong over the years. This demand is driven not just by the versatility of C# and its usage across various types of applications, but also by the continuous evolution and popularity of the .NET framework, which often goes hand-in-hand with C#. 

.NET, a free, cross-platform, open-source framework developed by Microsoft, is a favorite among developers for building a wide variety of applications, from web to mobile to gaming to IoT. Since C# is the main language used for .NET development, demand for C# often mirrors the demand for .NET developers. This is reflected in our 2023 Developer Skills Report, where C# ranks among the top 10 most in-demand programming languages, and .NET is listed among the most sought-after skills, growing in demand by 125% year over year.

Moreover, the introduction of .NET Core — a modern, cloud-optimized, and cross-platform version of the .NET framework — has further increased the demand for skilled C# developers. The .NET Core framework allows developers to build applications that can run on Windows, macOS, and Linux, which has expanded opportunities for C# programmers and further driven the need for their expertise in the job market.

For hiring managers, it’s crucial to note this interconnected demand for C# and .NET skills. When you find a candidate with strong C# abilities, it’s likely they also have a solid foundation in .NET, making them even more valuable to your team. The key takeaway here is that C# developers are in high demand due to the breadth and versatility of the language, its integral role in .NET development, and its expansive application across various domains. These factors all contribute to making C# a smart addition to any developer’s skill set and a valuable asset for any tech team.

Closing the Loop on C#: A Power Player in Your Tech Toolkit

C# has proven itself to be a robust, versatile, and highly desirable language. Its object-oriented nature, strong type system, and integration with the Microsoft ecosystem offer myriad possibilities for developers, whether they’re building a sophisticated enterprise application, an engaging video game, or a powerful web service.

As we’ve explored, C# forms a vital part of the .NET framework, making it indispensable in many tech stacks. The continuous evolution of .NET and its expanding application in cloud-based and cross-platform development has further amplified the value of C# skills in the job market. 

As a hiring manager, prioritizing candidates with proficiency in C# and an understanding of .NET can contribute significantly to your team’s ability to deliver innovative, efficient, and high-quality software solutions. For developers, diving into C# opens up a host of opportunities to contribute to a diverse range of projects and to stay competitive in today’s dynamic job market. Regardless of your perspective, taking a deep dive into C# not only equips you with valuable knowledge today, but positions you at the forefront of tomorrow’s opportunities, ready to tackle the next generation of software challenges.

This article was written with the help of AI. Can you tell which parts?

The post What Is C#? Unveiling the Magic of C# Programming appeared first on HackerRank Blog.

In the 40 years since its introduction, C++ has carved out its place in the infrastructure of many of our favorite software, systems, and games. Its unique blend of high-level and low-level language features, object-oriented paradigm, and raw power gives it a level of flexibility and performance that’s hard to match. As a result, C++ continues to be one of the most sought-after programming languages, with tech professionals globally striving to master it.

In light of its significance, excelling in C++ technical interviews becomes paramount for aspiring and seasoned programmers alike. These interviews act as gateways to coveted roles in the tech industry, and a deep understanding of C++ concepts, coupled with a knack for problem solving, can be your ticket to success.

In this blog post, we’ll delve into some essential C++ interview questions that test both your foundational knowledge and your understanding of advanced C++ concepts. These handpicked questions aim to mirror the kind of challenges you might face in a real C++ technical interview, whether you’re seeking a role in systems programming, game development, or any tech domain that calls for C++ expertise. By the end of this guide, you should be better equipped to impress in your next C++ coding interview. 

Understanding the C++ Interview

Roles that call for C++ proficiency span a wide range, from system-level roles to game development and even financial technology roles. These roles can include software engineers, back-end developers, quality analysts, game programmers, embedded engineers, and programming architects.  As part of the interview process for these positions, candidates will likely face C++ interview questions designed to gauge their depth of understanding and practical expertise as it pertains to the role.

Now, let’s delve into some of these critical C++ interview questions, ranging from intermediate to advanced levels. Each question will also come with a sample answer to provide practical insight into how you could tackle such problems in a live interview setting.

1. Attribute Parser

This challenge works with a custom-designed markup language HRML. In HRML, each element consists of a starting and ending tag, and there are attributes associated with each tag. Only starting tags can have attributes. We can call an attribute by referencing the tag, followed by a tilde, ‘~’, and the name of the attribute. The tags may also be nested.

The opening tags follow the format:

<tag-name attribute1-name = "value1" attribute2-name = "value2" ...>

The closing tags follow the format:

</tag-name>

The attributes are referenced as:

tag1~value  

tag1.tag2~name

Given the source code in HRML format consisting of N lines, answer Q queries. For each query, print the value of the attribute specified. Print “Not Found!” if the attribute does not exist.

Example

HRML listing

<tag1 value = "value">

<tag2 name = "name">

<tag3 another="another" final="final">

</tag3>

</tag2>

</tag1>


Queries

tag1~value

tag1.tag2.tag3~name

tag1.tag2~value

Here, tag2 is nested within tag1, so attributes of tag2 are accessed as tag1.tag2~<attribute>. The results of the queries are:

Query                 Value

tag1~value            "value"

tag1.tag2.tag3~name   "Not Found!"

tag1.tag2.tag3~final  "final"

Input Format

The first line consists of two space-separated integers, N and Q. N specifies the number of lines in the HRML source program. Q specifies the number of queries.

The following N lines consist of either an opening tag with zero or more attributes or a closing tag. There is a space after the tag-name, attribute-name, ‘=’, and value. There is no space after the last value. If there are no attributes there is no space after the tag name.

Q queries follow. Each query consists of a string that references an attribute in the source program. More formally, each query is of the form tagᵢ1 . tagᵢ2 . tagᵢ3 …. tagᵢm ~attr – name where m>=1 and tagᵢ₁ . tagᵢ₂ …. tagᵢm are valid tags in the input.

Constraints

1 ≤ N ≤ 20

1 ≤ Q ≤ 20

• Each line in the source program contains, at most, 200 characters.
• Every reference to the attributes in the Q queries contains at most 200 characters.
• All tag names are unique and the HRML source program is logically correct, i.e. valid nesting.
• A tag may have no attributes.

Output Format

Print the value of the attribute for each query. Print “Not Found!” without quotes if the attribute does not exist.

Sample Input

4 3
<tag1 value = “HelloWorld”>
<tag2 name = “Name1”>
</tag2>
</tag1>
tag1.tag2~name
tag1~name
tag1~value

Sample Output

Name1
Not Found!
HelloWorld

Solve the problem.

2. Inherited Code

You inherited a piece of code that performs username validation for your company’s website. The existing function works reasonably well, but it throws an exception when the username is too short. Upon review, you realize that nobody ever defined the exception.

The inherited code is provided for you in the locked section of your editor. Complete the code so that, when an exception is thrown, it prints Too short: n (where n is the length of the given username).

Input Format

The first line contains an integer, t, the number of test cases.

Each of the t subsequent lines describes a test case as a single username string, u.

Constraints

• 1 ≤ t ≤ 1000
• 1 ≤ │u│≤ 100
• The username consists only of uppercase and lowercase letters.

Output Format

You are not responsible for directly printing anything to stdout. If your code is correct, the locked stub code in your editor will print either Valid (if the username is valid), Invalid (if the username is invalid), or Too short: n (where n is the length of the too-short username) on a new line for each test case.

Sample Input

3

Peter


Me


Arxwwz

Sample Output

Valid
Too short: 2
Invalid

Explanation

Username Me is too short because it only contains 2 characters, so your exception prints Too short: 2.

All other validation is handled by the locked code in your editor.

Solve the problem.

3. Virtual Functions

This problem is to get you familiar with virtual functions. Create three classes: Person, Professor, and Student. The class Person should have data members name and age. The classes Professor and Student should inherit from the class Person.

The class Professor should have two integer members: publications and cur_id. There will be two member functions: getdata and putdata. The function getdata should get the input from the user: the name, age and publications of the professor. The function putdata should print the name, age, publications, and the cur_id of the professor.

The class Student should have two data members: marks, which is an array of size 6 and cur_id. It has two member functions: getdata and putdata. The function getdata should get the input from the user: the name, age, and the marks of the student in 6 subjects. The function putdata should print the name, age, sum of the marks, and the cur_id of the student.

For each object being created of the Professor or the Student class, sequential ID’s should be assigned to them starting from 1.

Solve this problem using virtual functions, constructors, and static variables. You can create more data members if you want.

Note: Expand the main function to look at how the input is being handled.

Input Format

The first line of input contains the number of objects that are being created. If the first line of input for each object is 1, it means that the object being created is of the Professor class. You will have to input the name, age, and publications of the professor.

If the first line of input for each object is 2, it means that the object is of the Student class. You will have to input the name, age, and the marks of the student in 6 subjects.

Constraints

1 ≤ lenname ≤ 100, where lenname is the length of the name.

1 ≤ age ≤  80

1 ≤ publications ≤ 100

0 ≤ marks ≤ ≤ 100, where marks is the marks of the student in each subject.

Output Format

There are two types of output depending on the object.

If the object is of type Professor, print the space-separated name, age, publications, and id on a new line.

If the object is of the Student class, print the space-separated name, age, the sum of the marks in 6 subjects, and id on a new line.

Sample Input

4
1
Walter 56 99
2
Jesse 18 50 48 97 76 34 98
2
Pinkman 22 10 12 0 18 45 50
1
White 58 87

Sample Output

Walter 56 99 1
Jesse 18 403 1
Pinkman 22 135 2
White 58 87 2

Solve the problem.

4. Operator Overloading

Classes define new types in C++. Types in C++ not only interact by means of constructions and assignments but also via operators. For example:

int a=2, b=1, c;

c = b + a;

The result of variable c will be 3.

Similarly, classes can also perform operations using operator overloading. Operators are overloaded by means of operator functions, which are regular functions with special names. Their name begins with the operator keyword followed by the operator sign that is overloaded. The syntax is: type operator sign (parameters) { /*… body …*/ }

You are given a main() function which takes a set of inputs to create two matrices and prints the result of their addition. You need to write the class Matrix, which has a member a of type vector<vector<int> >. You also need to write a member function to overload the operator +. The function’s job will be to add two objects of Matrix type and return the resultant Matrix.

Input Format

The first line will contain the number of test cases T. For each test case, there are three lines of input.

The first line of each test case will contain two integers N and M, which denote the number of rows and columns respectively of the two matrices that will follow on the next two lines. These next two lines will each contain N * M elements describing the two matrices in row-wise format, i.e. first M elements belong to the first row, next M elements belong to the second row, and so on.

Constraints

1<= T <= 1000

1 <= N <= 100

1 <= M <= 100

1 <= Ai,j <= 10, where Ai,j is the element in the ith row and jth column of the matrix.

Output Format

The code provided in the editor will use your class Matrix and overloaded operator function to add the two matrices and give the output.

Sample Input

1
2 2
2 2 2 2
1 2 3 4

Sample Output

3 4
5 6

Explanation

The sum of the first matrix and the second matrix is the matrix given in the output.

Solve the problem.

5. Abstract Classes – Polymorphism

Abstract base classes in C++ can only be used as base classes. Thus, they are allowed to have virtual member functions without definitions.

A cache is a component that stores data so future requests for that data can be served faster. The data stored in a cache might be the results of an earlier computation or the duplicates of data stored elsewhere. A cache hit occurs when the requested data can be found in a cache, while a cache miss occurs when it cannot. Cache hits are served by reading data from the cache, which is faster than recomputing a result or reading from a slower data store. Thus, the more requests that can be served from the cache, the faster the system performs.

One of the popular cache replacement policies is “least recently used” (LRU). It discards the least recently used items first.

For example, if a cache with a capacity to store 5 keys has the following state (arranged from most recently used key to least recently used key): 5 3 2 1 4

Now, if the next key comes as 1 (which is a cache hit), then the cache state in the same order will be: 1 5 3 2 4

Now, if the next key comes as 6 (which is a cache miss), then the cache state in the same order will be: 6 1 5 3 2

You can observe that 4 has been discarded because it was the least recently used key, and since the capacity of cache is 5, it could not be retained in the cache any longer.

Given an abstract base class Cache with member variables and functions:

• mp – Map the key to the node in the linked list
• cp – Capacity
• tail – Double linked list tail pointer
• head – Double linked list head pointer
• set() – Set/insert the value of the key, if present, otherwise add the key as the most recently used key. If the cache has reached its capacity, it should replace the least recently used key with a new key.
• get() – Get the value (will always be positive) of the key if the key exists in the cache, otherwise return -1.

You have to write a class LRUCache, which extends the class Cache and uses the member functions and variables to implement an LRU cache.

Input Format

The first line of input will contain the N number of lines containing get or set commands followed by the capacity M of the cache.

The following N lines can either contain get or set commands.

An input line starting with get will be followed by a key to be found in the cache. An input line starting with set will be followed by the key and value respectively to be inserted/replaced in the cache.

Constraints

1<= N <= 500000

1 <= M <= 1000

1 <= key <= 20

1 <= value <= 2000

Output Format

The code provided in the editor will use your derived class LRUCache to output the value whenever a get command is encountered.

Sample Input

3 1
set 1 2
get 1
get 2
Sample Output

2
-1

Explanation

Since the capacity of the cache is 1, the first set results in setting up the key 1 with its value 2. The first get results in a cache hit of key 1, so 2 is printed as the value for the first get. The second get is a cache miss, so -1 is printed.

Solve the problem.

6. C++ Variadics

A template parameter pack is a template parameter that accepts zero or more template arguments (non-types, types, or templates). To read more about parameter packs, click here.

Create a template function named reversed_binary_value. It must take an arbitrary number of bool values as template parameters. These booleans represent binary digits in reverse order. Your function must return an integer corresponding to the binary value of the digits represented by the booleans. For example, reversed_binary_value<0,0,1>() should return 4.

Input Format

The first line contains an integer, t, the number of test cases. Each of the t subsequent lines contains a test case. A test case is described as 2 space-separated integers, x and y, respectively.

• x is the value to compare against.
• y represents the range to compare: 64 × y to 64 × y + 63.

Constraints

• 0 ≤ x ≤ 65535
• 0 ≤ y ≤ 1023
• The number of template parameters passed to reversed_binary_value will be ≤ 16.

Output Format

Each line of output contains 64 binary characters (i.e., 0’s and 1’s). Each character represents one value in the range. The first character corresponds to the first value in the range. The last character corresponds to the last value in the range. The character is 1 if the value in the range matches x; otherwise, the character is 0.

Sample Input

2
65 1
10 0
Sample Output

0100000000000000000000000000000000000000000000000000000000000000
0000000000100000000000000000000000000000000000000000000000000000

Explanation

The second character on the first line is a 1, because the second value in the range 64..127 is 65 and x is 65.

The eleventh character on the second line is a 1, because the eleventh value in the range 0..63 is 10 and x is 10.

All other characters are zero because the corresponding values in the range do not match x.

Solve the problem.

7. Bit Array

You are given four integers: N, S, P, Q. You will use them in order to create the sequence a with the following pseudo-code:

a[0] = S (modulo 2^31)

for i = 1 to N-1

    a[i] = a[i-1]*P+Q (modulo 2^31) 

Your task is to calculate the number of distinct integers in the sequence a.

Input Format

Four space-separated integers on a single line, N, S, P, and Q respectively.

Output Format

A single integer that denotes the number of distinct integers in the sequence a.

Constraints

1 ≤ N ≤ 108

0 ≤ S, P, Q < 231

Sample Input

3 1 1 1
Sample Output

3

Explanation

a = [1,2,3]

Hence, there are 3 different integers in the sequence.

Solve the problem.

Resources to Improve C++ Knowledge

HackerRank C++ Practice Questions

HackerRank Interview

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The world of software development moves fast. Programming languages come and go like fashion trends. Yet, amidst this technological whirlwind, only a few languages have managed to weather the storm, standing as testaments to resilience and timeless utility. One such language is C++. 

Launched nearly 40 years ago, C++ is a formidable player in the world of coding, renowned for its efficiency, flexibility, and powerful control over hardware. Even as newer languages emerge, the demand for C++ remains robust, and its applications have only broadened with time, spanning from systems programming to game development and even artificial intelligence.

In this post, we’ll dive into the enduring world of C++. We’ll explore what C++ is, the key features that make it stand out, its advantages, and the diverse range of use cases it addresses. We’ll also delve into the crucial role it plays in today’s hiring trends, shedding light on the demand for C++ skills in the tech industry. Whether you’re a hiring manager aiming to understand the importance of C++ skills or a developer curious about the language’s possibilities, this post is your comprehensive guide to the fascinating world of C++. 

What is C++?

C++ is a statically typed, compiled, general-purpose programming language that’s been around since the early 1980s. It was invented by Bjarne Stroustrup as an extension of the C programming language, with the aim to incorporate the concept of “classes” and thereby facilitate object-oriented programming.

C++ is renowned for its efficiency and flexibility. One of its notable features is that it supports procedural programming, a style of programming where a problem is broken down into procedures, or sequences of instructions to be executed. This feature is particularly useful for tasks that require a lot of computational power, or in other words, tasks that keep the CPU — the brain of a computer — very busy. Furthermore, C++ provides developers with the ability to directly manage the computer’s hardware, such as memory, which is not often offered by many high-level languages. This control can result in highly efficient and faster programs.

At its core, C++ supports the creation of large, complex applications. It achieves this by providing a clear structure to programs and rich library support, enabling abstraction at different levels — from small to large scale — which is essential for developing complex real-world applications.

Due to its performance, efficiency, and backward compatibility with C, C++ is widely used in application and system software development. Examples include database software, operating systems, graphics and game development, embedded and real-time systems, and many more. 

Key Features of C++

Now that we’ve introduced C++, let’s delve into its defining characteristics. These unique features form the bedrock of the language and account for its enduring appeal among developers.

Object-Oriented

At the heart of C++ lies the concept of object-oriented programming (OOP). In OOP, real-world entities are modeled as objects that contain both data (attributes) and operations (methods). C++ supports the four fundamental principles of OOP: encapsulation, inheritance, polymorphism, and data abstraction. 

For example, let’s picture a car as an object. The car’s attributes might include its color, model, and speed, while its methods could be start(), stop(), and accelerate(). The OOP paradigm allows for better organization and more manageable code, which is especially handy when dealing with large software projects.

Memory Management

C++ puts a lot of power into developers’ hands, and one of the best examples is its memory management capabilities. It allows for both dynamic and static memory allocation. This means developers have the ability to allocate memory during runtime as well as compile time. While this freedom calls for responsibility, it enables the creation of highly efficient and performant applications.

High Level of Control

C++ doesn’t just hand you the keys to memory management; it gives you a high degree of control over the entire system. You can manipulate bits, bytes, and address spaces, which is crucial for system programming or scenarios where performance is paramount. This level of control is one reason why C++ is a popular choice for game development, where hardware interaction and real-time performance are key.

Compatibility with C

Inheritance isn’t just an OOP concept in C++; it’s part of the language’s history. C++ was actually developed as an enhancement of C, taking many of its fundamental features. This means that most C programs can be run in a C++ environment, giving developers the ability to use the tried-and-true efficiency of C while also benefiting from the additional features of C++, including object-oriented and generic programming. It’s this unique blend of old and new that gives C++ its power and flexibility.

Advantages of C++

While C++’s features set it apart, the language also offers several compelling advantages that draw developers and businesses alike. Here’s a look at why C++ has become such an enduring and popular language.

Speed

Perhaps one of the key advantages that C++ holds over other high-level languages is its blazing speed. It provides close-to-the-metal access, which essentially means the programmer has a high degree of control over system resources and memory — the sort of control that low-level languages offer. The less your program relies on the system to execute commands, the faster it can run, making C++ an optimal choice for performance-critical applications.

Scalability

C++’s ability to scale is another significant advantage. Its use of object-oriented programming allows for classes and objects, which are easier to manage, debug, and update than procedural code. This makes C++ a prime choice for large projects, where it’s vital to have code that’s not just efficient but also scalable and maintainable.

Versatility

C++ is an incredibly versatile language. Thanks to its compatibility with C, developers can easily switch between procedural and object-oriented programming, making it suitable for a wide variety of projects. This adaptability is something that few other languages offer, and it’s one reason why C++ has remained so popular over the years.

Community and Libraries

Last but not least, there’s the strong community and rich libraries that come with C++. Over the decades, a vibrant community of C++ developers has evolved, contributing to a wealth of resources and libraries. These open-source libraries can simplify development, offering pre-written code to solve common problems. This, combined with the broad community support, means that help is often just a forum post away.

Practical Use Cases of C++

Just as an architect can use the same set of tools to build a cozy cottage or a soaring skyscraper, C++ can be used to create a diverse range of applications. The language’s efficiency, speed, and ability to scale lend it to several different use cases. Let’s explore some of the practical scenarios where C++ is commonly used.

Game Development

C++ is a dominant player in the world of game development. Its speed and control over system resources enable developers to build high-performance games that provide smooth and responsive user experiences. Game engines like Unreal Engine, widely used for AAA game titles, are primarily written in C++.  

Graphic and User Interface (UI) Design

When it comes to developing graphical applications or designing user interfaces, C++ shines. The language’s versatility and power make it an excellent choice for building applications that require real-time, high-resolution graphics. Libraries such as Qt offer a host of tools for developing interactive graphical interfaces in C++. 

Real-Time Systems

Real-time systems — systems where the correctness of an operation depends not just on its logical correctness but also on the time it takes to execute — also rely heavily on C++. In situations like these, where system response times are critical, the efficiency and speed of C++ can be a game changer. Such systems range from aviation electronics and industrial process controllers to complex weapon systems and telecommunications networks.

AI and Machine Learning

Even in the field of artificial intelligence (AI) and machine learning, C++ has staked its claim. While Python might be the go-to language for many AI developers, the performance and scalability that C++ offers can often edge out its high-level counterparts. For instance, TensorFlow, one of the most popular machine learning libraries, provides a C++ API, acknowledging the language’s role in executing complex, data-heavy operations with superior performance.

Job Opportunities for C++ Developers

C++ programmers find themselves in high demand across a wide spectrum of industries. In HackerRank’s 2023 Developer Skills Report, C++ was the fourth most in-demand programming language. From tech giants to startups, many companies recognize the versatility and efficiency that C++ brings to the table:

• Software Development Companies: Major software companies, such as Adobe and Microsoft, hire C++ developers to work on their suite of desktop applications. Given the efficiency and performance of C++, it’s a language of choice for these high-end applications.
• Game Development Studios: The gaming industry often leans towards C++ for its efficient memory management and ability for real-time responsiveness, critical for game performance. Hence, game developers with C++ expertise are highly sought after.
• System Software Manufacturers: The ability to execute low-level tasks makes C++ an excellent choice for system software such as operating systems, file systems, and network drivers.
• AI and Machine Learning Firms: While Python and R have gained popularity in AI and machine learning, the efficiency and speed of C++ can’t be overlooked, especially in performance-critical applications. 

Key Takeaways

C++ isn’t just a language of the past; it continues to influence the present and will no doubt play a critical role in the future. The enduring demand for C++ skills in the job market affirms its relevance in today’s tech-driven world.

As we look ahead, the promise of C++ shines brightly. It’s a language that beckons those who crave power and control in their programming, providing the tools to shape technology and transform ideas into reality. And for those who master it, C++ opens the door to a wide array of opportunities, offering a pathway to innovation and advancement in the constantly evolving tech sphere.

Whether you’re a hiring manager looking for skilled C++ talent or a developer interested in honing your C++ skills, HackerRank’s roles directory is a valuable resource for exploring various tech roles and job families and learning more about the real-world skills shaping future innovations. 

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Amid a constellation of programming languages, Go has been carving out its own stellar path in recent years. Despite being a relatively new entrant in the world of programming, Go, with its focus on simplicity and efficiency, has swiftly climbed the ladder of popularity. In fact, according to Stack Overflow’s 2022 Developer Survey, Go is one of the most loved programming languages and ranks impressively high on the scale of most sought-after languages by employers worldwide. From networking services to data pipelines, distributed systems to cloud infrastructure, Go’s proficiency is versatile and influential.

But what is Go, exactly? In this blog post, we’ll explore Go’s genesis, its distinct features, the unique advantages it brings to the table, and its real-world applications. Whether you’re a hiring manager aiming to decode the intricacies of Go, or a tech professional aspiring to diversify your coding skills, this comprehensive guide will illuminate why Go has become a favored choice for many and how it continues to impact the future of software development.

What is Go?

Go — short for Golang — is a statically typed, compiled programming language designed to be simple, efficient, and reliable. The language was conceived in 2007 by Robert Griesemer, Rob Pike, and Ken Thompson at Google. Their aim? To make the process of coding quicker and more enjoyable, while retaining the power of complex languages like C++ and Java.

Go was born out of frustration with the complexity and sluggishness of other programming languages. The creators wanted something that could handle Google’s mammoth scale but without the headaches of long compile times, overcomplication, or messy dependencies.

While Go might sound like a back-to-basics language, it’s anything but primitive. Go is armed with an arsenal of powerful features that make it ideally suited for modern software development. It merges the ease of a dynamic, interpreted language like Python with the efficiency and security of a statically-typed, compiled language like C or C++.

But what makes Go stand out is its built-in support for concurrent programming — that is, the ability to handle multiple tasks at once. While other languages require complex code or external libraries to handle concurrency, Go has it baked right in, making it an excellent choice for tasks like network programming and real-time applications.

In a nutshell, Go is a powerful, efficient, and fun language that’s designed for the way software is written and deployed today. It’s built for speed, scale, and simplicity, striking a unique balance that’s captured the attention of developers and tech companies alike. 

Key Features of Go

Go’s rise in popularity is no fluke. It’s backed by some remarkable features that simplify programming tasks, enhancing both productivity and enjoyment for developers. Here are the key features that make Go stand out:

Simplicity

Go follows the philosophy of “less is more”. It provides a minimalistic and clean syntax, similar to that of C. This simplicity makes it easier for developers to read and write code, leading to fewer bugs and more maintainable codebases. For instance, the absence of classes and type inheritance makes Go’s type system easier to understand than that of more complex object-oriented languages.

Concurrency

Concurrency is the ability of a program to handle multiple tasks at once, which Go does elegantly. With Goroutines (functions that can run concurrently) and channels (used to safely communicate between Goroutines), Go makes concurrent programming more accessible and less error-prone. This is a godsend for modern applications dealing with several real-time tasks.

Fast Compilation

Go is a compiled language, which means it converts code into machine language before execution. However, unlike some other compiled languages, Go compiles at lightning speed. This leads to a swift feedback loop, allowing developers to see and fix their errors quickly. Imagine coding a large program and not having to wait an eternity to compile it. That’s the power of Go!

Garbage Collection

Memory management can be a headache in programming. Go tackles this issue with its built-in garbage collector that automatically manages memory, removing the objects that are no longer in use. This leads to safer code and less time spent on manual memory management.

Standard Library

Go comes with a rich standard library that covers a wide array of areas. From web server creation to cryptography, file I/O, and even image manipulation, Go’s standard library offers plenty of pre-written code that can save developers a lot of time.

Advantages of Using Go

Every programming language has its strengths and weaknesses, and Go is no exception. But what has made it a top choice for many companies and developers are its distinct advantages. Let’s explore what they are:s

Performance 

Go is a statically-typed, compiled language, meaning it often outperforms dynamically typed or interpreted languages. This makes it an excellent choice for programs that require high efficiency, such as data-intensive applications or network services.

Scalability

One of Go’s most remarkable features is its support for concurrent processing. This is crucial in an era where applications need to serve thousands or even millions of users simultaneously. Go’s design makes it easy to build systems that scale with demand, which is a big reason why companies with large-scale applications, like Dropbox and Docker, have adopted it.

Ease of Learning

Despite its power, Go is known for its simplicity. It was designed to be easy to learn, with a syntax that’s small enough to fit in your head. This lowers the barrier to entry, making it a great language for beginners and experienced programmers alike.

Powerful Tools

Go comes with a suite of powerful tools for tasks like debugging, testing, and documentation. Go’s toolchain also includes a formatter (gofmt) that automatically formats code, promoting readability and consistency across the codebase.

Excellent Community Support 

Go has a vibrant, growing community. This means you’ll find plenty of resources for learning Go, including tutorials, open-source projects, and libraries, as well as community support if you run into problems.

Common Use Cases for Go

Go’s versatility and efficiency have seen it adopted across a variety of sectors and for multiple use cases. Here are some common scenarios where Go truly shines:

• Cloud and Network Services: Go’s ability to handle concurrency elegantly and its strong network libraries make it an excellent choice for cloud services and networked applications. Companies like Google and Dropbox have used Go to build their cloud infrastructure. It’s also a popular choice for microservices, given its speed and ease of deployment.
• Command-Line Interfaces (CLI): CLI tools need to be fast and efficient. They should also be easily distributable as a single binary. Go’s static linking and swift execution make it an ideal choice for creating CLI tools.
• Data Pipelines: Go’s concurrency features and fast execution make it an ideal choice for building data pipelines. It allows you to efficiently process large amounts of data in real-time.
• Game Development: While it’s not as widely used as C++ for game development, Go’s simplicity and efficiency have led to its growing adoption in this field. Ebiten and Engo are popular Go libraries for game development.
• Web Development: With a powerful standard library that includes tools for web development, Go is a good choice for building robust web applications. It’s particularly suitable for back-end development, offering excellent support for handling requests and managing databases.

Go Hiring Trends

While it’s crucial to know what Go is and how it’s being used, it’s equally important to understand its place in the job market, especially if you’re a manager hiring for Go or a developer thinking about learning Go. Here are some of the key hiring trends to consider when it comes to Golang.

• High Demand: Given its strong performance characteristics and suitability for modern development tasks, demand for Go developers has skyrocketed. From startups to tech giants, companies are on the hunt for professionals adept at Go. In fact, our latest Developer Skills Report found that Go assessments grew by 301% in 2022.
• Competitive Salaries: Go is one of the top-paying programming languages. This is a testament to its value in building efficient, scalable software solutions. Learning Go could potentially open doors to lucrative job opportunities.
• Wide Industry Adoption: It’s not just the tech industry that’s embraced Go. Finance, media, and even academia have been using Go for various applications, increasing the opportunities for Go-skilled developers across different sectors.
• Future-Proof Skill: As we move towards an increasingly digitized future, the need for efficient, scalable, and reliable software will only grow. Languages like Go, designed with these needs in mind, are likely to be key tools in this future landscape.

Wrapping Up

From its inception at Google, Go has come a long way. It’s no longer just another programming language but a significant player in the tech industry. Its simplicity, efficiency, and built-in support for concurrent programming make it a versatile tool for everything from web servers to data pipelines and CLI tools. 

The rise of Go has significant implications for both hiring managers and tech professionals. For hiring managers, understanding the value of Go and how it can be used in your organization will help you recruit the right talent. For developers, learning Go could be a strategic move to open new opportunities and stay competitive in the job market.

Interested in learning more about tech roles that are driving the future of innovation? Visit HackerRank’s roles directory to explore various job families and tech roles, understand the skills required, and get a head start in this ever-evolving industry.

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The programming language Java has established itself as a cornerstone of the software development landscape. With its versatility, reliability, and widespread adoption, Java continues to be a powerful force driving innovation in the tech industry, despite being released nearly 30 years ago. In fact, Java ranks No.1 in the list of most-Googled technologies in 80 out of 162 countries worldwide and boasts a market share of over 50 percent in these countries. From web development to mobile app development, enterprise systems to big data processing, and even the Internet of Things (IoT), Java’s capabilities are far-reaching and impactful.

But what exactly is Java? In this blog post, we’ll delve into Java’s origins, key features, advantages, and real-world applications. Whether you’re a hiring manager seeking to better understand the realm of Java or a tech professional looking to broaden your skill set, this comprehensive guide will explain why Java has stood the test of time and how it continues to shape the future of software development.

What is Java?

Renowned as a versatile, object-oriented programming language, Java has left an indelible mark on the software development landscape since its inception. Created by James Gosling and his team at Sun Microsystems (now part of Oracle Corporation) in the mid-1990s, Java was designed to prioritize simplicity, portability, and scalability. These foundational principles have made Java an enduring and widely adopted language across various domains.

At its core, Java values simplicity in both its syntax and design. Its syntax is clean and intuitive, making it easier for developers to read, write, and understand code. Java’s syntax resembles that of the C and C++ programming languages, allowing programmers from those backgrounds to quickly grasp its structure. 

Key Features and Advantages of Java

Java’s enduring popularity can be attributed to its rich set of features and advantages that make it a preferred language for a wide range of projects. Here, we’ll explore some of the key characteristics that set Java apart and contribute to its success.

Platform Independence and Portability

Java’s “write once, run anywhere” (WORA) principle lies at the heart of its design philosophy. By compiling Java source code into platform-independent bytecode, Java programs can be executed on any platform that has a Java Virtual Machine (JVM) installed. This cross-platform compatibility allows developers to write code once and deploy it seamlessly on different operating systems, such as Windows, macOS, and Linux. Java’s portability simplifies the development process, reduces maintenance efforts, and promotes the reuse of code across diverse environments.

Robust Memory Management

Java takes care of memory management through its automatic memory allocation and garbage collection mechanism. Developers don’t need to explicitly allocate and deallocate memory, as Java’s runtime environment handles these tasks. The garbage collector identifies objects that are no longer referenced and frees up memory resources, preventing memory leaks and improving application stability. This built-in memory management system enhances the reliability and predictability of Java applications, freeing developers to focus on writing code rather than managing memory.

Object-Oriented Approach

Java’s strong support for object-oriented programming (OOP) enables developers to build modular, reusable, and maintainable code. The OOP paradigm promotes code organization, abstraction, and extensibility. Its features include:

• Encapsulation, which hides the internal details of an object, allowing for data protection and providing well-defined interfaces for interaction.
• Inheritance, which allows classes to inherit properties and behaviors from other classes, facilitating code reuse and promoting a hierarchical structure. P
• Polymorphism, which enables objects to exhibit multiple forms and behaviors, fostering flexibility, and supporting code extensibility.

Java’s embrace of OOP principles makes it an ideal choice for building complex and scalable applications.

Exception Handling

Java incorporates a robust exception-handling mechanism, allowing developers to handle errors and exceptional conditions effectively. Exceptions provide a structured approach to deal with unexpected situations that can occur during program execution. By using try-catch blocks, developers can handle exceptions gracefully, preventing application crashes and ensuring a more robust user experience. Java’s exception handling promotes the creation of reliable and fault-tolerant applications by facilitating error detection, reporting, and recovery.

Rich Standard Library and Ecosystem

Java offers a comprehensive standard library that provides a wide range of classes and APIs for common programming tasks. The Java Development Kit (JDK) includes libraries for I/O operations, networking, collections, concurrency, and more. These built-in tools save development time and effort by offering ready-to-use solutions for common programming challenges. Additionally, Java benefits from a thriving ecosystem of third-party libraries, frameworks, and tools. Popular frameworks like Spring, Hibernate, and Apache Struts provide higher-level abstractions, simplifying the development of web applications, enterprise systems, and more. The vast ecosystem of Java libraries empowers developers with a wealth of resources to enhance productivity, leverage specialized functionalities, and accelerate application development.

Multithreading and Concurrency

Java’s robust support for multithreading and concurrency allows developers to create efficient and responsive applications that can perform multiple tasks simultaneously. The Java concurrency model enables the execution of multiple threads within a single program, allowing for parallel processing and efficient utilization of system resources. Java provides built-in thread management mechanisms, synchronization constructs, and thread-safe data structures, making it easier to develop concurrent applications. With Java’s multithreading capabilities, developers can take advantage of modern hardware architectures and build high-performance applications that scale well with increasing demands.

Practical Use Cases of Java

Java’s versatility and robust feature set make it a versatile programming language that can be applied to a wide range of domains and use cases. Here are some practical applications where Java shines and continues to drive innovation.

Enterprise Software Development

Java has long been the language of choice for developing enterprise-level software systems. Its scalability, reliability, and extensive ecosystem of frameworks and libraries make it ideal for building large-scale, mission-critical applications. Java Enterprise Edition (Java EE), now known as Jakarta EE, provides a set of specifications and APIs for developing enterprise software, including features such as servlets, JavaServer Pages (JSP), Enterprise JavaBeans (EJB), and Java Persistence API (JPA). With Java EE, developers can create robust and scalable web applications, middleware, and back-end systems that can handle high traffic and complex business logic.

Web Development

Java’s web development capabilities are well-established, thanks to frameworks like Spring, JavaServer Faces (JSF), and Apache Struts. These frameworks provide developers with powerful tools for building web applications, handling requests, managing session state, and interacting with databases. Java-based web development is known for its stability, security, and support for industry standards. Whether it’s developing e-commerce platforms, content management systems, or enterprise web applications, Java’s web development frameworks offer a solid foundation for building robust and scalable solutions.

Android App Development

Java is the primary programming language for developing Android applications. Android Studio, the official integrated development environment (IDE) for Android, uses Java as its main language for building mobile apps. Java’s object-oriented nature, along with the Android SDK and libraries, provides developers with a powerful toolkit for creating feature-rich and interactive mobile applications. Java’s wide adoption in the Android ecosystem makes it a valuable skill for developers targeting the mobile app market.

Big Data and Analytics

Java plays a significant role in the big data and analytics landscape. Hadoop, a popular open-source framework for processing and analyzing large data sets, is built using Java. Java’s scalability, parallel processing capabilities, and compatibility with distributed computing systems make it an excellent choice for handling big data workloads. Additionally, Java libraries like Apache Spark and Apache Flink provide high-level abstractions and APIs for distributed data processing and real-time analytics. Java’s presence in the big data ecosystem enables developers to harness the power of data and derive valuable insights from massive datasets.

Financial and Trading Systems

Java has a strong foothold in the financial industry, where reliability, performance, and security are paramount. Many banking systems, trading platforms, and financial applications are built using Java. The language’s robustness, extensive libraries for data manipulation and encryption, and support for distributed computing make it an excellent choice for handling complex financial calculations, risk analysis, and algorithmic trading. Java’s ability to handle high transaction volumes and its mature ecosystem of financial libraries and frameworks position it as a top choice for building mission-critical financial systems.

Internet of Things (IoT) Development

With the rise of the Internet of Things (IoT), Java has emerged as a popular choice for developing IoT applications. Java’s ability to run on embedded systems and its support for network communication make it well-suited for IoT development. The lightweight Java Micro Edition (Java ME) platform provides a subset of Java technologies optimized for resource-constrained devices, making it ideal for IoT devices with limited processing power and memory. Java ME enables developers to create IoT applications that connect and interact with sensors, actuators, and other IoT devices, facilitating data collection, analysis, and control. Furthermore, Java’s extensive ecosystem of libraries, frameworks, and tools simplifies IoT application development, accelerating the time-to-market for IoT solutions.

Java’s Impact in the Job Market

Java is not only a powerful programming language but also a highly sought-after skill in the job market. In our 2023 Developer Skills Report, Java was the most in-demand programming language, based on volume of monthly active tests. Its versatility and wide range of applications have contributed to its significant impact in various industries and job roles and led to a continuous demand for professionals with Java expertise. 

To learn more about the skills and competencies needed for a range of Java positions, check out our roles directory.

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Python has soared in popularity and cemented its position as one of the most widely used programming languages in the tech industry. Known for its elegant syntax, readability, and versatility, Python has gained a vast community of developers and has become a go-to language for a wide range of applications, from web development and data analysis to machine learning and artificial intelligence.

As Python continues to dominate the programming landscape, it has become increasingly crucial for both hiring managers and Python developers to have a solid understanding of essential Python interview questions. These questions serve as a litmus test for assessing a candidate’s proficiency in Python programming and their ability to apply Python’s features effectively. By delving into Python interview questions, hiring managers can identify top talent, while developers can refine their skills and confidently demonstrate their abilities during job interviews.

In this article, we’ll guide you through a carefully curated collection of Python interview questions, unravel their solutions, and provide clear explanations and illustrative code snippets to help you tackle Python interviews with confidence.

What a Python Interview Looks Like

Python is a high-level, object-oriented programming language that was first introduced in 1991 by Dutch programmer Guido van Rossum. The language is well known — and loved — for its robust set of tools and libraries, which make it suitable for a wide range of applications and use cases. In addition, Python’s clean syntax and extensive community support have made it a preferred choice for both beginners and experienced developers.

A Python interview serves as an opportunity for hiring managers to assess a candidate’s Python programming skills, problem-solving abilities, and familiarity with Python’s ecosystem. While the specific format and structure may vary depending on the company and position, Python interviews typically consist of several components aimed at evaluating different aspects of a candidate’s capabilities. These can include:

• Technical screenings
• Coding challenges
• Whiteboarding exercises 
• Take-home assignments
• Pair programming sessions
• Behavioral interviews

Given Python’s versatility as a programming language, Python interview questions can come up in the hiring process for a number of technical roles, including software engineers, data scientists, data analysts, and machine learning engineers — to name just a few.

#1. Reverse Words in a Sentence

This question focuses on reversing the order of words in a given sentence, demonstrating a developer’s proficiency with string manipulation, loops, conditionals, and other programming constructs.

Task: Write a Python function called reverse_words that takes a sentence as input and returns the sentence with the order of words reversed.

Input Format: The input will be a string representing the sentence.

Constraints

• The sentence will contain only alphanumeric characters and spaces.
• There will be no leading or trailing spaces.
• The sentence will have at least one word.

Output Format: The output will be a string representing the sentence with the words reversed.

Sample Input: Python is awesome

Sample Output: awesome is Python

Sample Code

def reverse_words(sentence):

    words = sentence.split()

    reversed_sentence = ' '.join(reversed(words))

    return reversed_sentence

Explanation

• The reverse_words function starts by splitting the sentence into individual words using the split() method. This creates a list of words.
• Next, the function uses the reversed() function to reverse the order of the words in the list.
• The reversed words are then joined back together using the ‘ ‘.join() method, where the space character ‘ ‘ is used as the separator.
• Finally, the reversed sentence is returned.

#2. Maximum Subarray Sum

This question asks the developer to find the maximum sum of a subarray within a given array. Questions like this can be helpful for demonstrating a mastery of skills like analytical thinking optimization, algorithms, and array manipulation. 

Task: Write a Python function called max_subarray_sum that takes an array of integers as input and returns the maximum sum of any contiguous subarray within the array.

Input Format: The input will be a list of integers.

Constraints

• The length of the array will be at least 1.
• The array may contain both positive and negative integers.

Output Format: The output will be a single integer representing the maximum sum of a subarray.

Sample Input: [1, 2, 3, -2, 5]

Sample Output: 9

Sample Code

def max_subarray_sum(arr):     
max_sum = arr[0]     
current_sum = arr[0]     
for i in range(1, len(arr)):         
current_sum = max(arr[i], current_sum + arr[i])         
max_sum = max(max_sum, current_sum)     
return max_sum

Explanation

• The max_subarray_sum function utilizes Kadane’s algorithm to find the maximum sum of a subarray.
• It starts by initializing max_sum and current_sum to the first element of the array.
• Then, it iterates through the array, updating current_sum by either including the current element or starting a new subarray from the current element.
• At each iteration, max_sum is updated to store the maximum sum encountered so far.
• Finally, the function returns max_sum, which represents the maximum sum of any contiguous subarray within the given array.

#3. Merge Intervals

This question focuses on merging overlapping intervals within a given list, which gives recruiters insight into a developer’s ability to break down a complex problem, identify patterns, and design effective solutions, leveraging programming constructs like loops, conditionals, and list manipulation operations. 

Task: Write a Python function called merge_intervals that takes a list of intervals as input and returns a new list of intervals where overlapping intervals are merged.

Input Format: The input will be a list of intervals, where each interval is represented by a list with two elements: the start and end points of the interval.

Constraints

• The list of intervals will be non-empty.
• The start and end points of each interval will be integers.

Output Format: The output will be a list of merged intervals, where each interval is represented by a list with two elements: the start and end points of the merged interval.

Sample Input: [[1, 3], [2, 6], [8, 10], [15, 18]]

Sample Output: [[1, 6], [8, 10], [15, 18]]

Sample Code

def merge_intervals(intervals):     
intervals.sort(key=lambda x: x[0])     
merged = []     
for interval in intervals:         
if not merged or merged[-1][1] < interval[0]:             
merged.append(interval)         
else:             
merged[-1][1] = max(merged[-1][1], interval[1])     
return merged

Explanation

• The merge_intervals function sorts the intervals based on their start points.
• It initializes an empty list called merged to store the merged intervals.
• Then, it iterates through each interval in the sorted list.
• If the merged list is empty or the current interval does not overlap with the last merged interval, the current interval is appended to merged.
• If the current interval overlaps with the last merged interval, the end point of the last merged interval is updated to the maximum of the two end points.
• Finally, the function returns the `merged` list, which contains the merged intervals with no overlaps.

#4. Iterables and Iterators

Solve the Problem

The itertools module standardizes a core set of fast, memory efficient tools that are useful by themselves or in combination. Together, they form an iterator algebra making it possible to construct specialized tools succinctly and efficiently in pure Python.

To read more about the functions in this module, check out their documentation here.

You are given a list of N lowercase English letters. For a given integer K, you can select any K indices (assume 1-based indexing) with a uniform probability from the list.

Find the probability that at least one of the K indices selected will contain the letter: ‘a’.

Input Format: The input consists of three lines. The first line contains the integer N, denoting the length of the list. The next line consists of N space-separated lowercase English letters, denoting the elements of the list. The third and the last line of input contains the integer K, denoting the number of indices to be selected.

Output Format: Output a single line consisting of the probability that at least one of the K indices selected contains the letter: ‘a’.

Note: The answer must be correct up to 3 decimal places.

Constraints

• 1 ≤ N ≤ 10
• 1 ≤ K ≤ N

All the letters in the list are lowercase English letters.

Sample Input

4 

a a c d

2

Sample Output: 0.8333

Explanation

All possible unordered tuples of length 2 comprising of indices from 1 to 4 are:

(1, 2) (1, 3) (1, 4) (2, 3) (2, 4) (3, 4)

Out of these 6 combinations, 5 of them contain either index 1 or index 2, which are the indices that contain the letter ‘a’.

Hence, the answer is ⅚.

#5. Time Delta

Solve the Problem

When users post an update on social media, such as a URL, image, status update, etc., other users in their network are able to view this new post on their news feed. Users can also see exactly when the post was published — i.e, how many hours, minutes, or seconds ago.

Since sometimes posts are published and viewed in different time zones, this can be confusing. You are given two timestamps of one such post that a user can see on his newsfeed in the following format:

Day dd Mon yyyy hh:mm:ss +xxxx

Here +xxxx represents the time zone. Your task is to print the absolute difference (in seconds) between them.

Input Format: The first line contains T, the number of test cases. Each test case contains 2 lines, representing time t₁ and time t₂.

Constraints

Input contains only valid timestamps.

year ≤ 3000

Output Format: Print the absolute difference (t₁ – t₂) in seconds.

Sample Input

2

Sun 10 May 2015 13:54:36 -0700

Sun 10 May 2015 13:54:36 -0000

Sat 02 May 2015 19:54:36 +0530

Fri 01 May 2015 13:54:36 -0000

Sample Output

25200

88200

Explanation: In the first query, when we compare the time in UTC for both the time stamps, we see a difference of 7 hours, which is 7 x 3,600 seconds or 25,200 seconds.

Similarly, in the second query, the time difference is 5 hours and 30 minutes for time zone. Adjusting for that, we have a difference of 1 day and 30 minutes. Or 24 x 3600 + 30 x 60 ⇒ 88200.

#6. start() & end()

Solve the Problem

These expressions return the indices of the start and end of the substring matched by the group.

Code
>>> import re

>>> m = re.search(r’\d+’,’1234′)

>>> m.end()

4

>>> m.start()

0

Task: You are given a string S. Find the indices of the start and end of string k in S.

Input Format: The first line contains the string S. The second line contains the string k.

Constraints

0 < len(S) < 100

0 < len(k) < len(S)

Output Format: Print the tuple in this format: (start _index, end _index). If no match is found, print (-1, -1).

Sample Input

aaadaa

aa
Sample Output

(0, 1)  

(1, 2)

(4, 5)

#7. Decorators 2 – Name Directory

Solve the Problem

Let’s use decorators to build a name directory. You are given some information about N people. Each person has a first name, last name, age, and sex. Print their names in a specific format sorted by their age in ascending order, i.e. the youngest person’s name should be printed first. For two people of the same age, print them in the order of their input.

For Henry Davids, the output should be:

Mr. Henry Davids

For Mary George, the output should be:

Ms. Mary George

Input Format: The first line contains the integer N, the number of people. N lines follow each containing the space separated values of the first name, last name, age, and sex, respectively.

Constraints: 1 ≤ N ≤ 10

Output Format: Output N names on separate lines in the format described above in ascending order of age.

Sample Input

3

Mike Thomson 20 M

Robert Bustle 32 M

Andria Bustle 30 F

Sample Output

Mr. Mike Thomson

Ms. Andria Bustle

Mr. Robert Bustle

Concept: For sorting a nested list based on some parameter, you can use the itemgetter library. You can read more about it here.

#8. Default Arguments

Solve the Problem

In this challenge, the task is to debug the existing code to successfully execute all provided test files. Python supports a useful concept of default argument values. For each keyword argument of a function, we can assign a default value which is going to be used as the value of said argument if the function is called without it. For example, consider the following increment function:

def increment_by(n, increment=1):

    return n + increment

The functions works like this:

>>> increment_by(5, 2)

7

>>> increment_by(4)

5

>>>

Debug the given function print_from_stream using the default value of one of its arguments.

The function has the following signature:

def print_from_stream(n, stream)

This function should print the first n values returned by get_next() method of stream object provided as an argument. Each of these values should be printed in a separate line.

Whenever the function is called without the stream argument, it should use an instance of EvenStream class defined in the code stubs below as the value of stream.

Your function will be tested on several cases by the locked template code.

Input Format: The input is read by the provided locked code template. In the first line, there is a single integer q denoting the number of queries. Each of the following q lines contains a stream_name followed by integer n, and it corresponds to a single test for your function.

Constraints

• 1 ≤ q  ≤ 100
• 1  ≤ n ≤ 10

Output Format: The output is produced by the provided and locked code template. For each of the queries (stream_name, n), if the stream_name is even then print_from_stream(n) is called. Otherwise, if the stream_name is odd, then print_from_stream(n, OddStream()) is called.

Sample Input 

3

odd 2

even 3

odd 5

Sample Output 

1

3

0

2

4

1

3

5

7

9

Explanation: There are 3 queries in the sample. 

In the first query, the function print_from_stream(2, OddStream()) is executed, which leads to printing values 1 and 3 in separated lines as the first two non-negative odd numbers.

In the second query, the function print_from_stream(3) is executed, which leads to printing values 2, 4 and 6 in separated lines as the first three non-negative even numbers.

In the third query, the function print_from_stream(5, OddStream()) is executed, which leads to printing values 1, 3, 5, 7 and 9 in separated lines as the first five non-negative odd numbers.

Resources to Improve Python Knowledge

• HackerRank Python Practice Questions
• HackerRank Python Skills Certification
• HackerRank Interview

The post 8 Python Interview Questions Every Developer Should Know appeared first on HackerRank Blog.

The programming language Python has captured the hearts of developers worldwide with its simplicity, versatility, and widespread adoption. And despite having been released to the public more than 30 years ago, Python continues to grow in popularity today.

What makes Python stand out as a programming language is that it effortlessly combines elegance and functionality. Its clean syntax and expressive nature make coding a joy, enabling software developers to bring their ideas to life with clarity and efficiency. From web development to data science to machine learning, Python has become the go-to language for a wide array of applications, cementing its place as a favorite in the tech industry.

Whether you’re a seasoned coder looking to broaden your skill set or a hiring manager eager to understand Python’s allure, this blog post will serve as a comprehensive guide to this remarkable language. Below, we’ll shed light on Python’s origins, delve into its design philosophy, and uncover the unique features, advantages, and applications that set it apart, opening your eyes to the vast possibilities that this language has to offer.

What is Python?

Python is a high-level, general-purpose, object-oriented programming language renowned for its simplicity, readability, and versatility. Guido van Rossum, a Dutch programmer, created Python in the late 1980s with the vision of developing a language that prioritized ease of use and emphasized code clarity. Since then, Python has evolved into a powerful and widely adopted language, beloved by developers of all levels of expertise.

At its core, Python values simplicity. Its syntax — which are the rules that govern the structure of the symbols, words, and punctuation found in a programming language — is designed to be clean and straightforward, making it easy to read and write code. This simplicity not only enhances productivity but also encourages collaboration among developers. With Python, developers can focus on solving problems rather than wrestling with convoluted syntax or excessive boilerplate code.

Key Features and Advantages of Python

Python boasts several key features and advantages that contribute to its popularity and widespread adoption among developers. Let’s explore some of the notable characteristics that make Python a language of choice for a diverse range of projects.

Concise and Expressive Syntax

Python’s syntax is designed to prioritize code readability and conciseness. With its clean and uncluttered syntax, Python code is easy to understand and maintain. By minimizing the use of punctuation and relying on indentation for code blocks, Python encourages developers to write clean, well-structured code that is not only efficient but also more readable for both beginners and experienced programmers.

Extensive Standard Library and Rich Ecosystem

Python’s standard library provides a wealth of modules and functions that cover a wide range of tasks, including file I/O operations, networking, regular expressions, and more. This extensive collection of tools simplifies development by offering readily available solutions to common programming challenges.

Additionally, Python boasts a vibrant ecosystem of third-party packages. The Python Package Index (PyPI) hosts thousands of open-source libraries that cater to various domains, such as web development, data analysis, scientific computing, machine learning, and more. These packages — such as NumPy for numerical computing, TensorFlow for machine learning and artificial intelligence, or Django for web development — empower developers to leverage pre-built functionality and tackle complex challenges with ease.

Cross-Platform Compatibility and Portability

Python’s cross-platform compatibility is another advantage. It runs on various operating systems, including Windows, macOS, and Linux, allowing developers to write code once and deploy it seamlessly across different environments. This portability makes Python an excellent choice for projects that require platform independence or collaboration among diverse teams, and also simplifies deployment and reduces the effort required to support multiple environments.

Strong Community Support and Active Development

Python boasts a vibrant and supportive community of developers who actively contribute to its growth and improvement, creating a thriving ecosystem of resources, documentation, and open-source projects. Online forums, mailing lists, and social media platforms provide avenues for developers to seek help, share insights, and collaborate on projects. In addition, the Python Software Foundation (PSF) oversees the language’s development and ensures its continuous evolution, with regular updates and improvements.

Versatility for Various Applications

Python’s versatility is one of its greatest strengths. It offers a broad range of libraries and frameworks that cater to various domains and applications. And because it’s a general-purpose programming language, it can be used in a wide range of use cases, from building web applications and performing data analysis to developing machine learning models and scripting automation tasks.

Practical Use Cases of Python

So, what exactly are those use cases? In this section, we’ll explore some of the practical applications that highlight Python’s effectiveness and showcase how it drives innovation in various domains.

Web Development

Python’s web frameworks, such as Django and Flask, enable developers to build robust and scalable web applications efficiently. Django, a high-level framework, offers a “batteries-included” approach, providing features like Object-Relational Mapping (ORM), authentication, and admin interfaces out of the box. Flask, on the other hand, follows a micro-framework approach, offering flexibility and simplicity for smaller projects. Whether it’s developing e-commerce platforms, content management systems, or APIs, Python’s web development frameworks provide a solid foundation.

Data Analysis and Visualization

Python’s data analysis libraries, such as NumPy and Pandas, along with visualization tools like Matplotlib and Seaborn, make it a powerful language for working with data. Analysts and data scientists can leverage these libraries to explore and manipulate large datasets, perform statistical analysis, and generate insightful visualizations. Python’s data capabilities have helped revolutionize fields like finance, marketing, healthcare, and social sciences.

Machine Learning and Artificial Intelligence

Python has become the language of choice for machine learning and AI. Libraries like TensorFlow, PyTorch, and scikit-learn offer powerful tools for training and deploying machine learning models. Python’s simplicity, combined with these libraries, allows developers to experiment with different algorithms, build neural networks, and create intelligent systems that can recognize patterns, make predictions, and solve complex problems. From image recognition to natural language processing, Python is at the forefront of cutting-edge AI research and applications.

Scientific Computing

Python, along with libraries like SciPy and SymPy, is widely used in scientific computing. Researchers and scientists leverage Python’s numerical computing capabilities to solve mathematical equations, simulate physical systems, and analyze experimental data. The flexibility and extensibility of Python enable scientists to create custom algorithms, conduct simulations, and visualize results, accelerating advancements in fields such as physics, biology, and engineering.

Scripting and Automation

Python’s simplicity and extensive standard library make it an ideal choice for scripting and automation tasks. Whether it’s writing system administration scripts, automating repetitive processes, or performing data manipulation and file management, Python excels at boosting productivity. Its cross-platform compatibility ensures that scripts can be easily executed on different operating systems, simplifying deployment and collaboration.

Game Development

Python’s versatility extends to game development, with libraries like Pygame providing a framework for building 2D games and interactive applications. Python’s intuitive syntax and ease of use make it an attractive choice for hobbyists and indie game developers who want to bring their creative visions to life.

High Demand for Python Skills in Job Market Trends

Python has witnessed tremendous growth in recent years, becoming one of the most sought-after programming languages in the job market. In fact, in our 2023 Developer Skills Report, we found Python to be the second-most in demand programming language, based on volume of monthly active tests. Its versatility, ease of use, and extensive library ecosystem have made it a top choice for companies across industries. Here are some key reasons behind the high demand for Python skills:

• Data-Driven Decision Making: With the rise of big data and the increasing emphasis on data-driven decision making, Python’s capabilities in data analysis, machine learning, and artificial intelligence have become invaluable. Companies need Python developers who can leverage these skills to extract insights from data, build predictive models, and drive business growth.
• Web Development and Back-End Systems: Python’s web development frameworks like Django and Flask have gained significant traction. Python’s simplicity and scalability make it an ideal language for building robust web applications and back-end systems. As a result, companies are actively seeking Python developers who can create efficient and secure web solutions.
• Automation and Scripting: As we explored above, Python’s versatility shines in automation and scripting tasks. Its ease of use and extensive standard library make it a powerful tool for automating repetitive processes, handling system administration tasks, and performing data manipulation. Python developers who can streamline workflows and boost efficiency are highly valued.

Python’s impact in the tech hiring landscape cannot be understated. Its high demand in the job market stems from its versatility, efficiency, and its ability to drive innovation in numerous industries. Whether it’s leveraging Python for data-driven decision making, building robust web applications, automating tasks, or developing cutting-edge AI systems, Python developers bring a wealth of skills and value to companies.

This article was written with the help of AI. Can you tell which parts?

The post What Is Python? An Introduction to the Most Versatile Programming Language appeared first on HackerRank Blog.

The past few years have seen plenty of uncertainty in the tech industry. Yet even as the broader economic outlook appears to be softening, the demand – and competition – for skilled tech talent has only increased.

To get an unbiased, unparalleled view into the programming language popularity, HackerRank undertook an intensive study of our platform data. From the supremacy of Java and Python to the rise of Go and TypeScript, 2023 is on track to be a pivotal year for developer skills.

Methodology

Our ranking of the most popular programming languages draws from our 2023 Developer Skills Report. In that report, we used exclusive data from the HackerRank platform to understand employer demand, developer preference, and candidate engagement.

We tracked the popularity of languages by analyzing the languages candidates chose to use on assessments with multiple options available, as well as their proficiency in those languages. For key languages on our list, we’ve included data and insights on employer demand for the skill. We also included HankerRank Community practice data to get a full spectrum of skill preferences. The rates of change for data are based on the difference between volume in 2021 and 2022. In total, our analysis is based on the language preferences of 2.8 million developers.

The Most Popular Programming Languages

#1. Java

What this language is used for: 

• Mobile applications
• Cloud applications
• Video game development
• IoT devices
• Web-based applications
• Big data
• Machine learning

Java is a high-level, object-oriented programming language used to create complete applications. The language is platform independent, allowing it to run on any device that supports its environment. 

This combination of performance and versatility made Java the most popular programming language with developers in 2021 and 2022. You can do just about anything with Java. (Well, almost anything.) 

Building a machine learning model? Check. Developing IoT software for a smart fridge? Java has you covered. And of course, it’s the official language for Android development, the leading smartphone system in the world. Big data frameworks such as Apache Spark and Hadoop have also made Java a popular supporting skill for data scientists. Java usage is widespread, with companies such as Google, Netflix, Uber, and Spotify using the language.

Growing in popularity at a rate of 155%, Java is likely to retain its number one position for the foreseeable future.

#2. Python

What this language is used for: 

• Web development
• Data analysis
• Data visualization
• Task automation
• Machine learning

Python is an interpreted, high-level, general-purpose programming language, and one of the most popular languages for rapid development.

There are a number of reasons behind Python’s popularity with developers. It’s easy to learn, usable on nearly every project, and vital for the field of data science. There’s also a range of powerful Python frameworks, including Django, Bottle, Web2Py, and PyScript. Python usage is also widespread, with companies including Intel, IBM, Netflix, and Meta using the language.

#3. C++

What this language is used for: 

• Browser rendering
• Device operating systems
• Video game development
• Cloud systems
• Banking applications

C++ is a general purpose, compiled, and statically typed programming language. Known as “C with Classes,” C++ is an extension of C with the functionality of user-defined data classes. 

The high performance of C++ has made it the top language for use cases requiring fast rendering, including browsers, banking applications, and motion design software.

Another major contributor to C++’s ubiquity is its ability to work closely with system hardware. Developers use C++ as their first choice for hardware-oriented applications, including video game engines, operating systems, and cloud systems.

Another contributor to C++’s ubiquity is its age. C++ is more than 40 years old. In that time, it’s grown to support millions of applications, and developers have perfected it with new libraries and 20 updates. Beyond new application development, C++ skills are vital for maintaining existing applications and infrastructure. 

While C++ rounds out the medal podium with a third-place ranking, it’s unlikely to surpass Python anytime soon. Python utilization is almost 50% higher, and their growth rates are about the same.

#4. JavaScript

What this language is used for: 

• Web development
• Mobile development
• Interactive design
• Data visualization

JavaScript is a dynamic scripting language used for adding interactive behavior to web pages and applications. The main way developers use JavaScript is to manage the behavior and user experiences of websites. But there are a number of other interesting use cases for JavaScript. Node.js is a framework that extends the functionality of JavaScript to back-end, server-side applications. And libraries like D3.js make JavaScript useful for data visualization. There are also a range of powerful JavaScript frameworks, including, React, Angular, Vue, jQuery, ExpressJS, and Backbone.

JavaScript stands out as the first front-end language on our list. And you might be wondering why it doesn’t rank higher. After all, outlets like Stack Overflow and Codecademy rank JavaScript as the top language in the world. The difference is down to methodology.

Lists like Stack Overflow’s are survey-based, which means they measure the percentage of developers who know a language. In contrast, HackerRank’s list is based on the frequency at which developers choose to use a language. This provides visibility into both the languages that developers know and their likelihood to use them.

That’s not to say that JavaScript isn’t widespread. A staggering 97.3% of all websites use JavaScript as a client-side language. And with usage increasing at a rate of 157% per year, JavaScript’s popularity is only going to grow.

#5. C#

What this language is used for: 

• Mobile development
• Desktop development
• Web development
• Enterprise applications
• Cloud services
• Video game development

C# is a general purpose, object-oriented, component-oriented programming language developed around 2000 by Microsoft as part of its .NET initiative. C# is based on the C family of languages, and has similarities to C, C++, Java, and JavaScript. 

An extension of C, C# adds on a number of features, including variable checking, type checking, bound checking, and garbage collection. Like other members of the C language family, C# is a popular and well-established language, with companies such as Microsoft, Stack Overflow, Accenture, and Intuit using it in their tech stack.

#6. SQL

What this language is used for: 

• Relational database management

SQL is an industry-standard structured query language for creating, defining, implementing, accessing, and maintaining relational databases.

SQL has been growing at a steady rate of 133%, but was replaced in the top five by C#, which is growing at a rate of 173%.

SQL stands out on this list as the only database-oriented language in a crowd of front-end and back-end languages.

That fact goes a long way in explaining its placement on the list. It’s ubiquity as database management earns it strong popularity, but it’s too specialized to challenge the popularity of more versatile languages like Java, Python, and JavaScript.

#7. C

What this language is used for:

• Enterprise applications
• Operating systems
• Video game development
• Calculation-based applications
• Programming language development

C is a general-purpose, statically-typed, and compiled programming language. C is a foundational programming language that’s become known as the mother of all languages. Many of the most popular languages are built on C, including:

• C++
• C#
• Python
• Java
• JavaScript
• PHP
• Perl
• D
• Limbo
• Verilog

Because C has contributed to so many other languages, developers who learn C will acquire fundamental skills that transfer to any other language.

While the languages C inspired have surpassed it in popularity, the language is still a vital part of modern development.

#8. PHP

What this language is used for: 

• Web development
• Desktop app development

PHP is a widely-used open source and general-purpose scripting language that is especially suited for web development.

PHP’s popularity is owed to the fact that it was one of the first server-side languages that developers could embed into HTML. It’s also fast, secure, versatile, and supported by a strong open source community.

While PHP isn’t as popular as other general-purpose languages, its specialization gives it an advantage in web development over languages like Python.

#9. Go

What this language is used for:

• Cloud development
• Back-end development
• Distributed networks
• General development

Go is an object-oriented programming language that Google created in 2009 for networking and infrastructure. But since launch it’s evolved into a general-purpose language used in a wide range of applications.

Over a decade after Go’s launch, interest in the language has continued to grow. From 2018 to 2020, Go was the number one language developers wanted to learn. Companies such as Uber, Twitch, Dropbox, and – yes, Google – are using Go in their tech stack. 

Go stands out in this list as the second fastest-growing language. This year, Go overtook Swift’s spot at number nine. And it might have enough momentum to take PHP’s ranking in the near future. Go’s popularity is growing at a rate of 190%, while PHP is growing at 145%. Add in the fact that employer demand for Go increased by 301%, and its growth may even impact the popularity of other languages. 

 #10. Swift

What this language is used for: 

• iPhone app development
• MacOS app development

Swift is an open source, general-purpose programming language with a focus on performance, safety, and design patterns. Designed by Apple to replace Objective-C, Swift is the go-to language for iPhone, iPad, and Mac iOS development. 

Beyond iOS, Swift is a general-purpose language suitable for a wide range of use cases. However, drawbacks such as incomplete cross-platform support and poor interoperability with third-party tools limit its versatility.

Upon its launch, developers had hoped that Swift could challenge the popularity of Python. But Swift never quite caught on as a general-purpose language, and its usage levels reflect its role as a specialized technology. This is demonstrated by its decline in popularity from nine to ten in our list. Employer demand for Swift is also limited, with it ranking thirteenth in demand.

#11. Kotlin

What this language is used for: 

• Android development
• Back-end development
• Data science

Kotlin is a cross-platform, general-purpose programming language designed for safety, productivity, developer satisfaction, and Java interoperability. Kotlin is most known for its role in mobile development, with over 60% of Android developers using the language. 

Android apps that use Kotlin include Trello, Evernote, and Coursera. Beyond Android applications, developers use Kotlin for roles throughout the tech stack, including back-end development, full-stack development, and data science.

Kotlin popularity is on the rise, moving from twelfth to eleventh in popularity. However, its usage is far lower than classic languages like Java and Python. Employer demand for the language is also limited, as Kotlin doesn’t appear in our list of languages with the highest demand.

#12. Ruby

What this language is used for: 

• Web development
• Video game development
• Scientific computing
• Data processing
• Automation tools
• Data analysis

Ruby is an interpreted, dynamic, open-source programming language with a focus on simplicity and productivity. Ruby has a diverse range of use cases, including data-driven web apps, marketplaces, and desktop apps. 

Ruby is most known for Ruby on Rails (RoR), a framework optimized for productivity, efficiency, and DRY (Don’t Repeat Yourself). Developers have gradually shifted away from Ruby over the past several years, and it’s not surprising to see it drop from eleventh to twelfth in popularity. 

#13. TypeScript

What this language is used for: 

• Web development
• Mobile development
• Enterprise-level development

TypeScript is an open-source, object-oriented language that is an extension of JavaScript, meaning JavaScript code is valid TypeScript code. Developed by Microsoft in 2012, TypeScript describes itself as “all of JavaScript, and then a bit more.” 

The language builds on the foundation of JavaScript with additional features, including classes, object-oriented techniques, and scalable code bases. TypeScript has been gaining popularity for years, and ranked 4th in GitHub’s 2022 language rankings. 

From 2021 to 2022, TypeScript showed large gains in its popularity with developers. With a doubletake-inducing 2,788% gain, TypeScript is growing faster than any other programming language. That popularity is also translating into hiring demand. TypeScript demand grew by a huge 392% (or 282% compared to trend).

Its growth may also affect the growth of larger languages. TypeScript is tightly linked with JavaScript. Will its growth come at the expense of JavaScript, or will it serve to amplify it?

#14. Scala

What this language is used for: 

• Mobile development
• Web developments
• Big data systems
• IoT development

Scala is a high-level, statically-typed programming language that combines object-oriented and functional programming. Its multi-paradigm approach to programming makes it ideal for a number of use cases, including big data, distributed systems, Android applications, and IoT devices. A major benefit for developers is that Scala is interoperable with Java code and libraries.

#15. R

What this language is used for: 

• Statistical computing
• Data analysis

R is an open-source programming language for statistical computing and data analysis. Researchers and scientists use R for data visualization and statistical analysis in a number of industries, including academia, research, fintech, retail, government, healthcare, and social media.

The popularity of R has fallen over the past several years. From 2021 to 2022, R dropped from the thirteenth to the fifteenth most popular language. And while R grew by 59% in 2022, most other languages on this list are growing two to four times faster. 

The differences in total volume are even more striking. Only 1,239 developers opted to use R in their assessments. But 484 times as many developers used Java – almost 600k. The gap in relevance between these two languages is striking.

Given all these data points, we expect another language to replace R on this list in the near future.

Key Takeaways

• It’s unlikely that lower-ranked languages will break into the top five. The gap in volume is too great to overcome.
• Go and TypeScript are the languages to watch. Their popularity and demand are growing at a rate unmatched by other languages.
• Ruby, R, SQL, and Swift saw their rankings decrease. Their usage is still growing, just not fast enough.
• General-purpose languages like Java and Python tend to outrank more specialized languages like SQL and Swift. While the popularity of specialist languages is strong, their specialization means they’ll never reach the widespread usage of more popular languages. 

For more insights about trending languages and technical skills, read HackerRank’s 2023 Developer Skills Report.

The post The 15 Most Popular Programming Languages of 2023 appeared first on HackerRank Blog.

There’s a lot of information about what specific programming languages developers use. But language popularity doesn’t necessarily translate to employer demand. To get an unbiased, unparalleled view into the dynamic world of in-demand programming languages, HackerRank undertook an intensive study of our platform data. 

We found that, despite recent uncertainty in the tech industry, demand for skilled tech talent hasn’t slowed down. But demand for key skills and competencies isn’t distributed evenly. Heading into 2023, we have some key projections on how demand for certain skills is changing. 

No matter how you measure it, 2023 is on track to be a pivotal year for developer skills. From the rise of Go and TypeScript to the decline of Swift and Ruby, here are a few of those key trends. 

The Most In-Demand Programming Languages

#1. Java

Java is a high-level, object-oriented programming language used to create complete applications. The language is platform independent, allowing it to run on any device that supports its environment. 

In terms of growth relative to the market, demand for top-ranked Java is actually growing slightly slower than the market. But Java still leads second-ranked Python by a strong margin. Its first-place ranking is secure for the foreseeable future.

#2. Python

Python is an interpreted, high-level, general-purpose programming language, and one of the most popular languages for rapid development. Python usage is widespread, with companies including Intel, IBM, Netflix, and Meta using the language.

Demand for Python is catching up to demand for Java. While Java is growing slower than the market, Python grew relative to the market. While Python’s growth may mean that it narrows Java’s lead, the wide gap between them means we’re unlikely to see any place-trading.

#3. SQL

SQL is an industry-standard structured query language for creating, defining, implementing, accessing, and maintaining relational databases. In 2022, demand for SQL grew at a steady rate and managed to surpass C++. It’s also growing faster relative to the market. 

But while SQL improved its demand ranking, it decreased in its popularity ranking. SQL’s third-place demand ranking is noticeably higher than its sixth-place popularity ranking. The source of this gap in supply and demand is unclear. Interest in the SQL vs NoSQL debate has risen steadily over the last decade. Developers turning toward non-relational database systems could be a contributing factor.

#4. C++

C++ is a general purpose, compiled, and statically typed programming language. Known as “C with Classes,” C++ is an extension of C with the functionality of user-defined data classes. The high performance of C++ has made it the top language for use cases requiring fast rendering, including browsers, banking applications, and motion design software.

In 2022, C++ fell from third to fourth place, overtaken by SQL’s steady growth rate. Demand for C++ is also growing slightly slower relative to the market. However, demand for the language isn’t going anywhere. C++ skills are vital for maintaining existing applications and infrastructure.

#5. JavaScript

JavaScript is a dynamic scripting language for adding interactive behavior to web pages and applications. Primarily used for building interactive web experiences, JavaScript stands out as the first front-end language on our list.

At fifth place, JavaScript has nearly four times the volume of the sixth-ranked Bash. This calls attention to an important characteristic of this demand-based ranking. After the top five, there is a huge gap in volume, placing the leading programming languages in a category of their own. While JavaScript is growing slightly slower than the market, its top-five ranking is secure.

#6. Bash

Bash is a command-line language for Unix operating systems. The language allows developers (or anyone who works with data) to work with computer files directly instead of using a graphical user interface (GUI). This makes it a useful skill to learn for cloud engineers and data scientists.

Bash stands out on our list as the only in-demand language that did not rank in popularity with developers. It will be interesting to see how this misalignment between supply and demand will affect the job market. Will an abundance of opportunity and demand inspire developers to learn the language? Or will a small talent pool of developers skilled in the language force employers to pay a premium for their skills? In 2020 Bash was already correlated with higher compensation than popular languages like C, C++, C#, Python, and Java.

#7. C#

C# is a general purpose, object-oriented, component-oriented programming language developed in 2000 by Microsoft as part of its .NET initiative. C# is based on the C family of languages, and has similarities to C, C++, Java, and JavaScript. 

Demand for C# sits in the middle of the language family. C++ far exceeds C# in demand, but C# holds a notable lead over C.

#8. Go

Go is an object-oriented programming language that Google created in 2009 for networking and infrastructure. But since launch it’s evolved into a general-purpose language used in a wide range of applications.

Go has been gaining popularity with developers for several years. In 2022 it was the second fastest-growing language, with its popularity increasing at a rate of 190%. And that popularity is translating into hiring demand. Demand for Go grew by 301% in 2022. 

One potential side effect of Go’s success is that it might affect the growth of larger languages. Developers looking to learn a new general-purpose language might start choosing Go over languages with weak demand. (We’re looking at you, Ruby.)

It will be interesting to see if Go has the momentum to challenge the rankings of other languages on our list. While demand for Go is growing at 140% relative to the market, C# is only growing at 10% relative to the market. Though momentum is on Go’s side, the gap between the two languages might be too large to overcome in just a few years.

#9. TypeScript

TypeScript is an open-source, object-oriented language that is an extension of JavaScript. Developed by Microsoft in 2012, TypeScript describes itself as “all of JavaScript, and then a bit more.” 

TypeScript has been gaining popularity for years, and ranked 4th in GitHub’s 2022 language rankings. Like Go, we’re seeing that popularity translate into hiring demand. At 392%, TypeScript had the highest growth in demand of any programming language.

It will be interesting to see how TypeScript’s growth will affect JavaScript. The two are tightly linked. TypeScript’s growth could come at the expense of JavaScript, or it could serve to amplify it.

#10. R

R is an open-source programming language for statistical computing and data analysis. Researchers and scientists use R for data visualization and statistical analysis in a number of industries, including academia, research, fintech, retail, government, healthcare, and social media.

While it ranks low on our list, demand for R is growing. At about 60% relative to the market, it posted the fifth-highest growth in demand.

What’s interesting is that growing employer demand for R is misaligned with its falling popularity with developers.

From 2021 to 2022, R dropped from the thirteenth to the fifteenth most popular language – dead last on our list. And while R grew by 59% in 2022, most other languages we ranked grew two to four times faster. 

How will this conflict between supply and demand play out in the job market? Like Bash, we’ll be watching closely to see if growing demand inspires developer interest or raises the compensation for R skills.

#11. PHP

PHP is a widely-used open source and general-purpose scripting language that is especially suited for web development. PHP’s popularity is owed to the fact that it was one of the first server-side languages that developers could embed into HTML. 

While demand for PHP is low compared to other general-purpose languages, its growth rate is actually quite high. Demand for PHP grew at about 180% relative to the market, making it the second fastest-growing language, surpassed only by TypeScript. 

PHP might have enough momentum to challenge R and break into the top ten. PHP’s volume is only slightly lower than R’s, but it’s growing about three times faster relative to the market. This rise in demand may help correct PHP’s lagging compensation, which Stack Overflow ranked second to last in 2020 and 2021.

#12. C

C is a general-purpose, statically-typed, and compiled programming language. A foundational programming language, C has become known as the mother of all languages. 

While it ranks low on our list – third to last – demand for C is still growing. At about 70% relative to the market, C posted the fourth-highest growth rate out of any language. While it doesn’t have the volume or growth to surpass PHP in the near future, its place is secure against the two struggling languages that appear next on our list.

#13. Swift

Swift is an open source, general-purpose programming language with a focus on performance, safety, and design patterns. Created by Apple to replace Objective-C, Swift is the go-to language for Mac, iPhone, and iPad iOS development. 

In 2022, Swift had the second-largest decrease in demand. Its volume in 2022 was only 80% of what it was in 2021. Swift’s popularity is also limited, demonstrated by its drop from nine to ten in our list on language popularity. Taking both of these figures into account, we can see that Swift is in a state of decline. This can be attributed to the fact that Swift never quite caught on as a general-purpose language, and has had to settle for specialization in iOS development.

#14. Ruby

Ruby is an interpreted, dynamic, open-source programming language with a focus on simplicity and productivity. Ruby has a diverse range of use cases, including data-driven web apps, marketplaces, and desktop apps. 

In 2020 Ruby ranked fifth in Stack Overflow’s list of highest paying programming languages. But despite high compensation, demand for Ruby is declining. Its demand in 2022 was only 66% of what it posted in 2021. It’s also growing the slowest relative to the market out of any language on our list. Developers have gradually shifted away from Ruby over the past several years, and it’s not surprising to find its demand fading as well.

Ruby is already dead last in demand. If it continues at this rate, another language will inevitably take its place. 

Key Takeaways

• Python and Java rank first and second in both employer demand and popularity with developers. It’s interesting to note that supply and demand for these key languages are aligned.
• The gaps in volume between languages are significant, effectively dividing the list into four tiers:
  • The first tier consists of the top five languages (Java, Python, SQL, C++, and Java Script), which have enough volume to stand in a league of their own. 
  • The second tier (Bash and C#) sees a significant drop in volume, with Bash having only 25% of the volume of JavaScript. 
  • The third tier (Go, TypeScript, R, and PHP) have similar demand levels and are growing the fastest. 
  • Rounding out the list is the fourth tier (C, Swift, and Ruby), whose languages barely post enough volume to rank on the list.

Methodology

Our ranking of the most popular programming languages draws from our 2023 Developer Skills Report. In that report, we used exclusive data from the HackerRank platform to understand employer demand, developer preference, and candidate engagement.

We tracked the demand for languages by analyzing the number of tests requiring developers to use a specific language. For some languages we also reference their popularity with developers, which is based on the languages candidates chose to use on assessments with multiple options available. The rates of change for data are based on the difference between volume in 2021 and 2022. In total, our analysis is based on tests taken by 700,000 developers.

The post The Most In-Demand Programming Languages for 2023 appeared first on HackerRank Blog.