C#

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C# is a modern, object-oriented language with lots of great features, such as type-inference and async/await. The tooling is excellent, and there is extensive, well-written documentation.
Track mentors

17 Mentors

Our mentors are friendly, experienced C# developers who will help teach you new techniques and tricks.
Track students

3,671 Students

Join thousands of students who have enjoyed learning and improving their skills by taking this track.
Track exercises

114 Exercises

Hundreds of hours have gone into making these exercises fun, useful, and challenging to help you enjoy learning.

About C#

C# is a multi-paradigm, statically-typed programming language with object-oriented, declarative, functional, generic, lazy, integrated querying features and type inference.

Statically-typed means that identifiers have a type set at compile time--like those in Java, C++ or Haskell--instead of holding data of any type like those in Python, Ruby or JavaScript.

Object-oriented means that C# provides imperative class-based objects with features such as single inheritance, interfaces and encapsulation.

Declarative means programming what is to be done, as opposed to how it is done (a.k.a imperative programming) (which is an implementation detail which can distract from the domain or business logic).

Functional means that functions are first-class data types that can be passed as arguments to and returned from other functions.

Generic means that algorithms are written in terms of types to-be-specified-later that are then instantiated, when needed, for the specific types provided as parameters.

Lazy (a.k.a "deferred execution") means that the compiler will put off evaluating an item until required. This lets one safely do weird stuff like operating on an infinite list--the language will only create the list up to the last value needed.

Integrated Querying means the language feature called LINQ "Language-Integrated Query", which enables lazy querying directly within the language, not only its own objects but, also, external data sources through formats such as XML, JSON, SQL, NoSQL DBs and event streams.

Type inference means that the compiler will often figure out the type of an identifier by itself so you don't have to specify it. Scala and F# both do this.

Syntax is similar to that of other C-style languages such as C, C++ and Java.

.NET is the managed environment within which C# runs, so you get access to the entire .NET ecosystem, including all packages on nuget.org. .NET used to be Windows-only but, with the release of .NET Core -- as well as Mono -- you can also use C# on Mac, Linux or Unix-based systems and on mobile platforms too.

C# also has features, amongst others, to make programming with multiple threads/processors, parallelisation, asynchrony, unmanaged code in a managed environment and language interoperability easier. It is developed and maintained by Microsoft, who provides the official documentation.

Join the C# track
class HelloWorld
{
    string Hello()
    {
        return "Hello, World!";
    }
}

The c# markdown problem is my favourite

The c# markdown problem is my favourite, it is sufficiently complex to be interesting, and is similar to a lot of the code that I see. Writing good quality code from scratch is generally easier than refactoring existing bad quality code to make it good.

Relaxed. Encouraging. Supportive.

Meet the C# Track mentors

Once you join the C# language track, you will receive support and feedback from our team of mentors. Here are the bios of a few of the mentors of this track.

Avatar of Jo Van Eyck

Jo Van Eyck https://github.com/jovaneyck

Software crafter, legacy code wrestler. I help companies get things done without shooting themselves in the foot and teach others how to do it. I use C# professionaly.
Avatar of Steven Atkinson

Steven Atkinson https://github.com/mrstebo

I began my professional programming career with VB.NET, but have spent the rest (over 8 years) happily working with C#.
Avatar of Christoph Lipp

Christoph Lipp https://github.com/ser1us

I use C# for all my IoT projects and my native apps (Xamarin). It has a very big ecosystem and frameworks like ASP.NET Core can be used as a very good alternative to Node.js.
Avatar of Erik Schierboom

Erik Schierboom My blog

I am a developer with a passion for learning new languages. C# is a well-designed and expressive language that I love programming in.
Avatar of René Wernicke

René Wernicke https://github.com/renao

I love talking code. C# professional by day, learning new languages by night.
Avatar of Nathan Chere

Nathan Chere NathanChere.com.au

Worked as a software developer since mid 2000's across various platforms and languages, with roughly 7 years of experience as a developer/consultant focusing primarily on .NET
Fun. Challenging. Interesting

Community-sourced C# exercises

These are a few of the 114 exercises on the C# track. You can see all the exercises here.

Dominoes
medium
arrays
tuples
Circular Buffer
medium
classes
queues
Zipper
hard
recursion
searching
trees
Accumulate
easy
extension methods
sequences
transforming
Roman Numerals
medium
control flow loops
transforming
Gigasecond
easy
dates
Passionate. Knowledgeable. Creative.

Meet the C# Track maintainers

The C# Maintainers are the brains behind the C# Track. They spend their spare time creating interesting and challenging exercises that we can all learn from. We are incredibly grateful for their hard work. Here are the bios of a few of the maintainers of this track.

Rob Keim

I stumbled upon this site when I was trying to learn about functional programming and F#. Little did I know, I'd wind up becoming a contributor and learning a whole lot more than what I originally intended to. I had never contributed to an open source project before, and it's been a very rewarding experience.

John Reese I sometimes write about stuff

I am a software engineer with a passion for testing and C#. If you have any questions about the C# track or the language in general, feel free to ask; I'd love to hear them.

Erik Schierboom My blog

I am a developer with a passion for learning new languages. C# is a well-designed and expressive language that I love programming in.

Get started with the C# track. As with everything on Exercism, it's 100% free!

Join the C# Track