Sign in Get started

C# Tutorial · C# Basics · Lesson 1 of 22

C# Introduction

What C# and .NET are, what you can build, and a first program.

What is C#?

C# (pronounced "C sharp") is a modern, object-oriented, statically typed language from Microsoft. It runs on .NET, a free, open-source, cross-platform runtime for Windows, macOS and Linux.

With C# you can build:

  • Web APIs and websites with ASP.NET Core
  • Games with Unity
  • Desktop and mobile apps with .NET MAUI and WPF
  • Cloud services, background workers and command-line tools

Hello, World!

Hello, World!
Console.WriteLine("Hello, World!");

Output

Hello, World!

Run this on your computer — see “Get Started” for setup.

Modern C# uses top-level statements: the code in Program.cs runs directly, without writing a Main method yourself. C# examples on this site show the program and its output.

Test yourself

Which runtime does C# run on?

  1. The JVM
  2. .NET
  3. Node.js
  4. The browser
Show answer

Answer: .NET