#include <stdbool.h>
#include <stdio.h>

#define X(Y) ((Y)?"true":"false")

int main(){
  printf("(int)true: %d\n",(int)true);
  printf("(int)(_Bool)6: %d\n",(int)(_Bool)6);
  printf("6 == true: %s\n",X( 6 == true ));
  printf("((_Bool)6) == 1: %s\n",X( ((_Bool)6) == 1 ));
  printf("!!6 == 1: %s\n",X( !!6 == 1 ));
  printf("!!6 == true: %s\n",X( !!6 == true ));
  return 0;
}

(int)true: 1
(int)(_Bool)6: 1
6 == true: false
((_Bool)6) == 1: true
!!6 == 1: true
!!6 == true: true