I can try to explain by giving you some examples:
lets say that you have two variables:
int x;
float y;
if you want to cast "x" so it became a float variable,you would have to use this: y = ( float )x;
if you want to cast "y" so it became an int variable,
you could use this: x = ( int )y;
So if you have a variable "z" of "type1",if you want to convert it to "type2": you could use z2 = ( type2 )z;
( z2 is a variable of type2 )
I hope that this will help !