Why do you expect them to have different runtimes?

++i and i++ only differ if you actually use their values, something like j = ++i (which is equivalent to j = i+1; i++) vs. j = i++ (which is equivalent to j = i; i++). Other than that they do exactly the same thing

Basically, because the condition of stopping in your loop is checked before the increment of i, and after the increment of i (either i++ or ++I), I increases by 1.