Subtraction without minus sign in C

Question

How can I subtract two integers in C without the - operator?

Answer 1

Given that encoding integers to support two's complement is not mandated in C, iterate until done. If they want you to jump through flaming hoops, no need to be efficient about it!

int subtract(int a, int b)
{
  if ( b < 0 )
    return a+abs(b);
  while (b-- > 0)
    --a;
  return a;
}

Silly question... probably silly interview!