What do F and D mean at the end of numeric literals?

Question

I\'ve seen some of this symbols, but I cannot find anything strange with it,

double d = 5D;
float f = 3.0F;

What does the D and F behind 5

Answer 1

As others have mentioned they are the Type definitions, however you will less likely see i or d mentioned as these are the defaults.

float myfloat = 0.5; 

will error as the 0.5 is a double as default and you cannot autobox down from double to float (64 -> 32 bits) but

double mydouble = 0.5;

will have no problem