What is the use of `default` keyword in C#?

Question

1. What is the use of default keyword in C#?
2. Is it introduced in C# 3.0 ?

Answer 1

The default keyword has different semantics depending on its usage context.

The first usage is in the context of a switch statement, available since C# 1.0:
http://msdn.microsoft.com/en-us/library/06tc147t(VS.80).aspx

The second usage is in the context of generics, when initializing a generic type instance, available since C# 2.0:
http://msdn.microsoft.com/en-us/library/xwth0h0d(VS.80).aspx