你好,我对以下代码有些困惑:
int main()
{
int sum = 0, val = 1;
while(val <= 10)
sum += val, ++val; //source of problem
cout<<"Sum of 1 to 10 inclusive is " << sum << endl;
//
return 0;
}
我目前正在学习运算符优先级。知道逗号运算符是C++运算符中优先级最低的,我希望在下面的while循环语句中,该语句按照以下顺序进行评估:
++val; //so that val is incremented to 2 the first time the code in the while loop is evaluated
sum += val; //so that the incremented value of val is added to the sum variable
但是实际执行的顺序却如下所示:
sum += val;
++val;
为什么逗号运算符似乎会影响表达式的求值顺序?
sum += ++val;
,这样就没有歧义了,每个人都知道你的意思了? - NathanOliver++val; sum += val;
。 - Nicol Bolas