What is the quick formula(s) way for evaluating no. of times a loop will be processed without actually evaluating the loop? I suggest you to read some books which contain the algorithm analysis. From your example, I know that it is required 0(n) which n representing the times of the for loop. Hope this help
I may be way off here but wouldn't (x+1)-y = z work? This of course would only work if the ending value is greater then the starting value, and it is a >= statement. Is this just an general thought? Or are you looking for code for this too?