#include <assert.h>

#define BIT_DEL(x, n)    ((x) &= ~(1<<(n)))
#define BIT_SET(x, n)    ((x) |=  (1<<(n)))
#define BIT_TOGGLE(x, n) ((x) ^=  (1<<(n)))

int main() {
  int foo;

  foo = 42;

  /* Delete bit 5 */
  BIT_DEL(foo, 5);
  assert(foo == 10);
  BIT_DEL(foo, 5);
  assert(foo == 10);

  /* Set bit 5 again */
  BIT_SET(foo, 5);
  assert(foo == 42);
  BIT_SET(foo, 5);
  assert(foo == 42);

  /* Set bit 0 */
  BIT_SET(foo, 0);
  assert(foo == 43);

  /* Delete bit 0 */
  BIT_DEL(foo, 0);
  assert(foo == 42);

  /* Toggle bit 5 */
  BIT_TOGGLE(foo, 5);
  assert(foo == 10);
  BIT_TOGGLE(foo, 5);
  assert(foo == 42);
}