What do two left-angle brackets "<<" mean in C#?

Question

Basically the questions in the title. I'm looking at the MVC 2 source code:

[Flags] public enum HttpVerbs {     Get = 1 << 0,     Post = 1 << 1,     Put = 1 << 2,     Delete = 1 << 3,     Head = 1 << 4 } 

and I'm just curious as to what the double left angle brackers << does.

Answer 1

When you write

1 << n 

You shift the bit combination 000000001 for n times left and thus put n into the exponent of 2:

2^n 

So

1 << 10 

Really is

1024 

For a list of say 5 items your for will cycle 32 times.