Immediate Input

[VenomousNinja]

Hey.
Okay, so I'm working on a calculator program, and in order for it to work like I want it to, I need it to get input immediately, before the user presses enter.

I know there's a way to do it with <iostream>, I've seen the code before, I just can't remember what it is.
Help?

[Gumbercules]

I don't think it can be don with iostream, but I'd love to know if I'm wrong. It definitely can be done with conio.h (dos) getch()