When does a pre/post increment occur?
Both ++x and x++ increment the value of x. The difference is whether you evaluate the value of x in your expression (formula) before or after incrementing it.

int x1 = 0;
int y1 = 0;

int x2 = x1++; //Post-increment: Move current value of x1 (0) to x2, THEN increment x1
int y2 = ++y1; //Pre-increment: Increment y1. Then move the NEW value of y1 (1) to y2.


In the above, x2 will be 0, and y2 will be 1.

The same logic applies to your if expression. If you use pre-increment, your if statement makes its decision on the new value after incrementing it.

If you use post-increment, the if statement makes its decision based on the value before it's incremented.