C# (pronounced "C Sharp") is an object-oriented programming language developed by Microsoft Corporation as part of their .NET initiative in response to the success of Sun Microsystems' Java programming language. C# source code—as well as those of other .NET languages—is compiled into an intermediate byte code called Microsoft Intermediate Language (MSIL).
Primarily, C# is a hybrid of the C, C++, and Java programming languages with some features of Microsoft Visual Basic thrown into the mix. Like its Java ancestor, C# features automatic garbage collection (GC), scalability, simplified type declarations, type safety, and versioning support plus a few new features for Microsoft COM+ and Web services development.
Hewlett-Packard, Intel, and Microsoft submitted the Microsoft C# Specification to both European Computer Manufacturers Association (ECMA) and the International Standards Organization (ISO). In time, it was approved as a standard by ECMA and called the Standard ECMA-334 C# Language Specification. The C# language was architected by Anders Hejlsberg—a Delphi designer—, Scott Wiltamuth, and Peter Golde.
You will notice that we sometimes use the term "CSharp" instead of "C#". Unfortunately, some software cannot handle the sharp sign (#) in certain contexts. For example, this wiki software cannot handle the sharp sign in internal links. Therefore, we use "CSharp" when necessary. The two terms are synonymous.
