I haven't tried this for RobotC, but when you're writing console programs, you can use the '\b' escape character to delete the previous character. It is how Tetris can be done on cmd.exe

Again, I don't know if this works on RobotC, and I don't have it installed on this machine.
_________________FTC Team 6424, the 'Oly Cow - Chief programmer.
FRC Team 4450, Olympia Robotics Federation (ORF).
and also quadrotors. Quadrotors!