//Lets declare i, and set it equal to 4.
int i = 4;

//Now say their is a function nammed goFetch(int), and we wanted to pass an increment of i to it

//i = 4 before this code gets touched, the value 4 would be passed, and then i would become 5
goFetch(i++);

//i = 4 before this code gets touched, i gets incrimented before anything else (and becomes 5), and the value 5 would be passed
goFetch(++i);

So, ++i means to incriment first then give the incrimented value, and i++ means to give the original value, then incriment.