If you don't see the difference, I recommend that you run a 'diff' program over the code. If you see the difference, but don't understand it, then I recommend that you ask a specific question.
I have previously recommended that you investigate scope, particularly as it relates to auto variables. One may attempt to avoid the drawbacks of automatic variables by resorting to global or static keywords, but such measures are often dangerous and ineffective.
At some point in this exercise, you are going to have to go sit behind the barn and watch the cotton grow while you reflect on the realities of the language. Take a reference book with you.