/* -------------------------
   Flip a certain bit
   ------------------------- */

#include <stdio.h>

int main( int argc, char* argv[] )
{
   char a = 31;         /* a = 00011111 (= 31) */

   /* ====================================
      Flip the bit x: 000x1111
      Xor with:       00010000
      ==================================== */
   a = a ^ 0b00010000;  /* Now: a = 00001111 (= 15) */       
    
   printf( "a =  %d\n", a  );
    
   /* ====================================
      Flip the bit x back: 000x1111
      Xor again with:      00010000
      ==================================== */
   a = a ^ 0b00010000;  /* Now: a = 00011111 (= 31) */       
    
   printf( "a =  %d\n", a  );
}