This type of thing is a PITA (Pain In The Ascii) to do in the console. You can find ways to directly poll the input stream with external libraries but I suggest you start learning GUI libraries instead. With a GUI you have simple event handling that would allow you to respond when a uses types a character into a text box for instance.
EDIT: If you REALLY need to do this in a console program check into conio and curses (pcurses and ncurses are later versions). They offer functions that will help... at least in Windows.