c++ - char 的 std::cin 导致无限循环

Question

我在 switch 之前的 cin 之后使用了 cout 语句来确定我遇到了第二个数字和字符 op 的问题，并且由于某种原因我进入了无限循环!!!我感觉我在语法上犯了一个小错误，但我不知道是什么。

#include<iostream>
using namespace std;
int main()
{
    float a, b;
    char op, ans;
    do {
    cout << "Enter first number, operator, second number: ";
    cin >> a;
    cin >> b;
    cin >> op;
    cout << "first number is: " << a << "second number is: " << b << "operator is: " << op;
    switch (op) {
    case '/':
        cout << "answer = " << a / b << endl;
        break;
    case '*':
        cout << "answer = " << a * b << endl;
        break;
    case '+':
        cout << "answer = " << a + b << endl;
        break;
    case '-':
        cout << "answer = " << a - b << endl;
        break;
    }
    cout << "again? Y/N";
    cin >> ans;
    } while (ans != 'N' || ans != 'n');

    cout << endl;
    system("pause");
    return 0;
}

Answer 1

并且永远不等于 n 或 N。您的 OR 条件总是会通过为真。尝试将其切换为

    while(ans == 'Y' || ans == 'y')