That is some interesting results. How did a even get touched in all that? And did you happen to find out why b is 12?
The compiler is free to push variables into the stack in any order it wants. VC++ usually maintains the order, but GCC doesn't. GCC prefers to group similar variables together.
Like I said, it's most likely that b+12 == &i. Although answering the question "why do demons fly out of your nose?" with "because they wanted to get some pizza" is rather missing the point.
It may be beneficial to watch some of the Stanford University lectures on programming paradigms. Lecture 3 has some info on arrays but it is probably worth starting at lecture 2. Don't bother with lecture 1, it is admin stuff for the course.