gistfile1.txt

#include <stdio.h>
#include <stdlib.h>

#define swap_bytes(first, second) char* temp = malloc(sizeof(char)); *temp = *(char*)first; *(char*)first = *(char*)second; *(char*)second = *temp; free(temp);

int main()
{
  char a = 'a';
  char b = 'b';
  printf("%c, %c\n", a, b);
  swap_bytes(&a, &b);
  printf("%c, %c\n", a, b);
}