when i use float gg =10f;// flaot gg = 10;

[giribabu rosi]

tell me?

[Tom Johnson]

Default for floating point numbers is double so to put data into a float u have to explicitly tell compiler this.
However its not needed it the value you're putting in is same size or smaller than float.

 
float myFloat1 = 190.245f;  // OK
float myFloat2 = 190;       // OK as float and int are the same size

myFloat1 explicitly indicated as a float, without it there is a compile error as double 190.245, the default without the f suffix, wont fit into float

//tom