如何在一个循环中确定年度税收的计算？

Question

我需要写一个项目记录健身房的会员费。健身房每年收费1,200美元，基本费用，但根据您的会员等级，每年收取一个百分点的费率:金会员1%，银会员2%，铜牌会员4%

它将显示以下菜单：

欢迎来到隆达的Strikeforce健身房！！

会费计算器

1. 黄金
2. 银牌
3. 青铜
4. 退出

请输入您的会员级别(1-3输入4退出)>

所列菜单项的验证输入，如果输入1到3，程序将使用一个循环输出成员未来10年的预期费用。输出格式是一个具有相应年份和会员费的表。程序应该继续循环，直到用户准备退出为止。我应该将代码封装在一个并发循环中。如果输入4，则程序应该退出。任何其他输入都应该将错误消息显示为输出。我的输出不是从1200的基数开始，而是从百分比中的因素开始的。在程序的另一次迭代中，最后计算的值被用作起点。

这就是我所拥有的：

//Assignment 4-A.cpp: The program will calculate the membership fees over the next 10 years based on the membership level

#include <iostream>
#include <iomanip>
using namespace std;

int main() // Driver program

{
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);
    //To hold menu choice
    const int GOLD = 1,
        SILVER = 2,
        BRONZE = 3,
        QUIT = 4;
    //To hold the percentage tax of the different gym choices
    const double tax_gold = .01,
        tax_silver = .02,
        tax_bronze = .04;
    //To hold the base charge per year
    const double base_charge = 1200.00;
    //variables
    double fees = 0, cost = base_charge, cost_1 = 1200.00;
    //To hold the users input
    int user_input;
    const int min_number = 1,
              max_number = 10;
    int i;

    do
    {

        cout << "\t Welcome to Ronda's Strikeforce Gym!!" << endl; //Title

        cout << "x";

        for (int i = 0; i <= 50; i++) //Dashed line, row
        {
            cout << ("-");
        }

        cout << "x";

        cout << endl;

        cout << "\t Membership Fee Calculation" << endl; //Title

        //Display of gym membership plan choice
        cout << "1. Gold" << endl;
        cout << "2. Silver" << endl;
        cout << "3. Bronze" << endl;
        cout << "4. Quit" << endl << "\n";

        cout << "Please enter your membership level (1-3  Enter 4 to Quit) ";
        cin >> user_input;

        cout << endl;

        // Validate user input(must input 1 through 4), loop if value is invalid
        while (user_input < 1 || user_input > 4)
        {
            cout << "Invalid entry! ";
            cout << "Please enter a selection from 1 through 4: ";
            cin >> user_input;

            cout << endl;

        }

        // If values 1 - 3 were entered perform calculations else if 4 was entered exit program with thank you message.
        // Perform calculation for specified membership for 10 years and output
        if (user_input == 4)
        {
            break;

        }

        if (user_input != QUIT)
        {
            //Start selection loop and calculation
            switch (user_input)
            {
            case 1:
                fees = base_charge * tax_gold;
                cost = base_charge + fees;
                break;
            case 2:
                fees = base_charge * tax_silver;
                cost = base_charge + fees;
                break;
            case 3:
                fees = base_charge * tax_bronze;
                cost = base_charge + fees;
                break;
            }

            //Display Yearly Cost
            for (int years = 1; years <= 10; ++years)

            {
                cout << "Year   " << years << "\t $" << (cost_1 += fees) << endl;

            }

            cout << "\n";

        }

    } while (user_input != QUIT);
        {

        cout << "Thank you for using Ronda's Fee Calculator! \n";

        }
    
    cout << endl;

    cout << "Press any key to continue . . .";

    return 0;
}

这就是我的电脑上显示的：在这里输入图像描述

这就是它应该看起来的样子：在这里输入图像描述

谢谢

Answer 1

您的计算应该从基本费率(cost = 1200)开始。每年，打印当前税率，然后添加税率*税。(cost += cost * tax)。

下面是一些修改后的代码：

//To hold menu choice
const int GOLD = 1, SILVER = 2, BRONZE = 3, QUIT = 4;
//To hold the percentage tax of the different gym choices
const std::array<double, 3> tax_rates{.01, .02, .04};
//To hold the base charge per year
const double base_charge = 1200.00;

while (true) {
    cout << "\t Welcome to Ronda's Strikeforce Gym!!\nx";   //Title
    for (int i = 0; i <= 50; i++)   //Dashed line, row
    {
        cout << ("-");
    }
    cout << "x\n\t Membership Fee Calculation\n";   //Title
    //Display of gym membership plan choice
    cout << "1. Gold" << endl;
    cout << "2. Silver" << endl;
    cout << "3. Bronze" << endl;
    cout << "4. Quit" << endl << "\n";
    
    cout << "Please enter your membership level (1-3  Enter 4 to Quit) ";
    int user_input;
    cin >> user_input;
    cout << endl;
    
    // Validate user input(must input 1 through 4), loop if value is invalid
    while (user_input < 1 || user_input > 4)
    {
        cout << "Invalid entry! ";
        cout << "Please enter a selection from 1 through 4: ";
        cin >> user_input;
        cout << endl;
    }
    
    // If values 1 - 3 were entered perform calculations else if 4 was entered exit program with thank you message.
    // Perform calculation for specified membership for 10 years and output
    if (user_input == QUIT)
    {
        break;
    }
    
    //Display Yearly Cost
    double cost = base_charge;
    for (int years = 1; years <= 10; ++years)
    {
        cout << "Year   " << years << "\t $" << cost << endl;
        cost += cost * tax_rates[user_input-1];
    }
    cout << "\n";
}

cout << "Thank you for using Ronda's Fee Calculator!\n\nPress any key to continue . . .";

附带注意:建议您不要对货币使用浮点值。FP可以引入舍入误差。您可以在货币的基本面值中使用整数。美元是美分(便士)。只是为了将来的项目要注意的事情。