int Add(int x, int y)
{
  // Iterate till there is no carry
  while (y != 0)
  {
  // carry now contains common set bits of x and y
  int carry = x & y;

  // Sum of bits of x and y where at least one of the bits is not set
  x = x ^ y;

  // Carry is shifted by one so that adding it to x gives the required sum
  y = carry << 1;
  }
  return x;
}


int Add(int x, int y)
{
  if (y == 0)
  return x;
  else
  return Add( x ^ y, (x & y) << 1);
}