C# is an elegant and type-safe object-oriented programming language that enables developer to build a variety of secure and robust applications on the top of .NET Framework. It was developed by the team which was led by Anders Hejlsberg. C# was first appeared on 2000 AD.
Hello World program in C#
Differences between C# and .NET
C# is a general purpose object-oriented programming language like Java, C++ etc which runs on the .NET Framework. Where as .NET is a blanket term that tends to cover both the .NET Framework(an application framework library) and the Common Language Runtime which is the runtime in which .NET assemblies run.
.NET isn't just a library, but also a runtime for executing applications.
i.e. .NET Framework includes a large class library named Framework Class Library (FCL) and provides user interface, data access, database connectivity, cryptography, web application development, numeric algorithms and network communications.