Operations to boolean

test.cpp

#include <stdio.h>
int
main(void){
  bool t = true;
  printf("%d\n",t << 1);  //=> 2
  printf("%d\n",++t);  //=> 1
  printf("%d\n",t);  //=> 1
  int i = 1;
  printf("%d\n",i << 1);  //=> 2
  printf("%d\n",++i);  //=> 2
  printf("%d\n",i);  //=> 2
}