bits.c

#include <stdio.h>


unsigned char swap_bits(unsigned char octet)
{
  return (octet >> 4) | (octet << 4);
}

int main()
{
  unsigned char a = 10;

  a = swap_bits(a);
  char i = sizeof(unsigned char) * 8; // 8
  /*
  00001010 10
  00000100 1 << 2
& 00000000

  00000001 1 << 0
  00000010 1 << 1
  00000100 1 << 2
  00001000 1 << 3
  00010000 1 << 4
  00100000 1 << 5
  01000000 1 << 6
  10000000 1 << 7
  */

  /*
    00001010

    00000000 >> 4
    10100000 << 4


    00000000
    10100000
  | 10100000
  */

  while (i > 0)
  {
    // printf("%d\n", 0 != (a & (1 << i)));
    putchar('0' + (0 != (a & (1 << (i - 1)))));
    i--;
  } 
  putchar('\n');

  return (0);
}
/*
** i want pancakes!!!!NOOOOO
** BUT WHY!!!!!!
*/