void printBits8(char x)
{
   for (int i = 7; i >= 0; i--)
      if ( x & (1<<i) ) 
          putchar('1');
      else
          putchar('0');
}

void printBits16(short x)
{
   for (int i = 15; i >= 0; i--)
      if ( x & (1<<i) ) 
          putchar('1');
      else
          putchar('0');
}

void printBits32(int x)
{
   for (int i = 31; i >= 0; i--)
      if ( x & (1<<i) ) 
          putchar('1');
      else
          putchar('0');
}