//dziala
void bin(unsigned long int x)
{
   if (x < 2)
   {
      printf("%d", x & 1);
      return;
   }
   bin(x >> 1);
   printf("%d", x & 1);
}

//nie dziala
void bin(unsigned long int x)
{
   bin(x >> 1);
   printf("%d", x & 1);
}