Integer raise-to-power-of

Don't cast back and forth to double just to use Math.Pow(). Seriously.

public static int Exp(this int x, int y)
{
 int result = 1;
 while (y > 0)
 {
 if ((y & 1) != 0)
 {
 result *= x;
 }
 y >>= 1;
 x *= x;
 }
 return result;
}