c++ - 在if语句C++中意外中断

Question

该程序将日元，欧元或英镑(取决于用户输入)转换为美元。
我要问2个用户输入-双倍金额(要转换的货币)和char货币(以确定要转换为美元的货币)。
样本输入:1y
样本输出:1日元= 0.0094美元。
问题出在if-else块中，当我尝试将欧元转换为美元时，它打破了while循环。这是我的代码:

double amount; // the amount of money to be converted
char currency; // to determine the currency in which the money is being entered in.
    while (cin >> amount >> currency) {
        if (currency == 'y' || currency == 'Y') {
            cout << amount << " yen(s) = " << (amount * 0.0094) << " dollar(s).\n";
        }
        else if (currency == 'e' || currency == 'E') {
            cout << amount << " euro(s) = " << (amount * 1.13) << " dollar(s).\n";
        }
        else if (currency == 'p' || currency == 'P') {
            cout << amount << " pound(s) = " << (amount * 1.25) << " dollar(s).\n";
        }
        else {
            cout << "Sorry I did not recognize the currency! Please enter 'y','e' or 'p'.\n";
        }
        cout << "Please enter the amount of money and corresponding currency to covert to  dollars: ";
    }

作为证据，这里是我输入和输出的图像:
欧元转换为美元错误一

欧元转换为美元错误二

Answer 1

提供实际答案，因为我无法在评论中提供；这是获取相关用户输入并保持相同语法的另一种方法。假定输入字符串的最后一个字符是货币字符。您可以检查最后一个字符是否是有效的货币字符，但这是简化的版本。

#include <iostream>
#include <string>

int main() {
    std::string input_string;
    std::getline(std::cin, input_string);

    if(input_string.size() >= 2) {
        char currency = input_string[input_string.size() - 1];
        input_string[input_string.size() - 1] = '\0';
        double amount = std::stof(input_string);

        std::cout << amount << std::endl;
        std::cout << currency << std::endl;
    }
}