int main(int argc, const char * argv[]) {
int a = 3,b = 4,result = -1;
// a < 3和b < 3都为真,&&的结果才为真
result = a < 3 && b > 3;
printf("result= %d\n",result);
result = a < 3 || b > 3;
printf("result= %d\n",result);
result = ! a > 3;
printf("result= %d\n",result);
result = !!!a;//!(!(!a))
printf("result= %d\n",result);
return 0;
}