Yeah, I'm pretty sure he's in the "has to" boat. As a student, if your teacher says "do it this way", you kinda need to "do it that way" or risk failing the assignment. He hasn't said anything about which OS he's using here either, and what he's doing here is OS/compiler specific. So if they tell him to use bios.h, as I said earlier, they've probably already told him what compiler he's supposed to use.
It doesn't do him any good to program it in Win32 if his teacher isn't compiling for Windows, now does it?
Quzah.