C++编写货币转换器程序运行结果不符合预期求助

你代码里的汇率换算逻辑搞反了乘法和除法的使用场景，具体问题如下：

• 选项1是EGP转USD，你定义的egpToUsd = 0.064意思是1 EGP可以兑换0.064 USD，正确的计算应该是金额 × 汇率，你写反成了除法
• 选项3是EGP转SAR，你定义的egpToSar = 0.24意思是1 EGP可以兑换0.24 SAR，正确计算应该是金额 × 汇率，你错误用了除法
• 选项6是SAR转USD，你定义的sarToUsd = 0.27意思是1 SAR可以兑换0.27 USD，正确计算应该是金额 × 汇率，你错误用了除法

#include <iostream>
using namespace std;

int main()
{
    cout << "1- EGP TO USD" << endl;
    cout << "2- USD TO EGP" << endl;
    cout << "3- EGP TO SAR" << endl;
    cout << "4- USD TO SAR" << endl;
    cout << "5- SAR TO EGP" << endl;
    cout << "6- SAR TO USD" << endl;

    int num;
    double balance;

    double egpToUsd = .064;
    double usdToEgp = 15.70;
    double egpToSar = .24;
    double usdToSar = 3.75;
    double sarToEgp = 4.19;
    double sarToUsd = .27;

    cout << "Enter a Num: ";
    cin >> num;
    cout << "Enter your balance: ";
    cin >> balance;

    if (num >= 1 && num <= 6)
    {
        switch (num)
        {
        case 1:
            cout << (balance * egpToUsd);
            break;
        case 2:
            cout << (balance * usdToEgp);
            break;
        case 3:
            cout << (balance * egpToSar);
            break;
        case 4:
            cout << (balance * usdToSar);
            break;
        case 5:
            cout << (balance * sarToEgp);
            break;
        case 6:
            cout << (balance * sarToUsd);
            break;
        }
    }
    else {
        cout << "Error please select from list" << endl;
    }

    return 0;
}

用100 EGP转USD测试：100 × 0.064 = 6.4 USD，和实际汇率换算结果一致。

内容的提问来源于stack exchange，提问作者Mohamed ElHussein