What Is C#?

C# ("C sharp") is a statically-typed, object-oriented language created by Microsoft, running on .NET — a managed runtime with its own garbage collector, similar in spirit to Java's JVM.

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

That single line is a complete, runnable C# program — modern C# (via top-level statements, since C# 9) no longer requires the class/Main boilerplate older tutorials show, though a larger project still typically organizes code into classes exactly like Java does.