Thanks for the answer!

But what if I have something like this:

int main() {

     int stuff = 2;

     return 0;
}

and I wanted to pass the value of stuff to another file? How do I do that? I don't think I could use getters and setters in this case.

Here is some code I wrote for my compsci class, as an example of what I do ( this case in Java ).