Letter after a number, what is it called?

Question

What is this called?

double  d1 = 0d;
decimal d2 = 0L;
float   d3 = 0f;

And where can I find a reference of characters I can use? If I want

Answer 1

Here's the reference of the decimal type in C#:

http://msdn.microsoft.com/en-us/library/364x0z75(v=VS.100).aspx

And here's the reference of the "Standard Numeric Format Strings", which is what you are asking about:

http://msdn.microsoft.com/en-us/library/dwhawy9k.aspx