Yes, that's what it's for. Instead of making the function call each time, the compiler expands it "inline" in the code where it was called. As you might expect, too much inlining can bloat your code.
It's good that you are inquisitive and want to learn new things. I wasn't trying to bust your chops.
If you *really* want to impress your teacher, though, download UnitTest++ and verify that your code works with automated unit tests. Or code up your own test harness to drive your code and validate it.