Code:
FONT* arial = "Arial#8";

Put this in the code.

And replace PANEL* panDisplay with this:
Code:
PANEL* panDisplay =
{
	digits(35, 10, "a = %0.f", arial, 1, a);
	digits(35, 19, "b = %0.f", arial, 1, b);
	digits(35, 28, "c = %0.f", arial, 1, c);
	flags = VISIBLE;
}