c++ - 简单的c++连续计算器，无法退出程序

Question

我用 C++ 制作了这个简单的计算器。它连续接受输入，但我在将我的操作变量定义为 char 时遇到了麻烦，因为它让我无法退出程序。这是代码:

#include <iostream>

 int main(){
    long double num1, num2; char operation;
    std::cout << "Welcome to the calculator!\n\nInput numbers and operations to begin. (2+2) Then hit enter.\n\nThe calculator will continue to expect an operation and number (e.g. +6)\nuntil you enter \"q\" as an operation.\n\nEnter \"q\" as an operation to quit.\n\n";
    std::cin >> num1 >> operation >> num2;
    do{
        switch(operation){
            case '+':
                num2 += num1;
                break;
            case '-':
                num2 -= num1;
                break;
            case '/':
                num2 /= num1;
                break;
            case '*':
                num2 *= num1;
                break;
            default:
                std::cout << "Not a valid operation. Try again.";
                break;
        }
        std::cout << num2;
    } while (std::cin >> operation >> num1);
    return 0;
} 

程序运行良好，运行良好，只是不知道如何退出。我试过让“q”成为返回 0 的案例，但它似乎不起作用，因为我的 do-while 需要 2 个输入...有什么想法或想法吗？

Answer 1

std::cin >> num1 >> operation >> num2;
do
{
switch(operation){
case '+': num2 += num1; break;
case '-': num2 -= num1; break;
case '/': num2 /= num1; break;
case '*': num2 *= num1; break;
default: std::cout << "Not a valid operation. Try again."; break; }
std::cout << num2;
std::cin >> operation;
if (operation == 'q') break;
else std::cin >> num1;
}
while (1);

示例 I/O3+47+310q结尾3+4