Looks good :) Your coding is easily readable and organized.
Here's a few ideas:
After each test you have return 0; which quits the program. You could eventually use a while() loop that can keep the program going until the user presses a certain button to quit. Then you would have return 0; only at the very end - where it usually should be.
system("pause"); is bad in general. It takes a lot of resources and it not portable (ie: it sux). For c++ use cin.get() .
Oh and i meant to add that u shouldn't use system() at all. Cheers