C ++程序確定稅金

Question

因此，該代碼應要求用戶輸入其收入，無論是共同報稅還是單獨報稅，輸出總收入和所得稅，然后詢問用戶是否要重做或退出。 但是由於某種原因，它會迫使您在每次輸入之前繼續輸入兩次。 我知道我可能缺少一些簡單的代碼問題，但我無法弄清楚。 使用Visual Studio，請幫忙！

int main()
{
    double income = 0;
    double taxRate = 0;
    double add = 0;
    double subtract = 0;
    double incomeTax = 0;
    string taxStatus = "";
    string file = "";
    string answer = "";
    top:
    cout << "\nPlease enter your income to calculate your taxes\n " << endl;
    cin >> income;
    while (!(cin >> income)) //get input
    {
        if (isdigit(income))
        {
            break;
        }

        else
        {
            //if input fails, run this
            cin.clear();
            cin.sync();
            cout << "\nSorry, that was not a valid number. Please enter a valid number\n ";
        }
    }
    cin.ignore(80, '\n');

    cout << "\nIf you will be filing singly, enter 's'. If you will be filing jointly, enter 'm'\n ";
    cin >> file;
    while (!(cin >> file)) //get input
    {
        if (file == "s" || "m")
        {
            cin.ignore(80, '\n');
            break;
        }

        else
        {
            //if input fails, run this
            cin.clear();
            cin.sync();
            cout << "\nThat is not a correct input, please enter s/m\n ";
        }
    }

        if (file == "s")
        {
            if (income <= 863)
            {
                taxRate = .022;
                subtract = 0;
                add = 0;
            }

            if (income >= 864 & income <= 2588)
            {
                taxRate = .033;
                subtract = 863;
                add = 25;
            }

            if (income >= 2589 & income <= 4313)
            {
                taxRate = .062;
                subtract = 2588;
                add = 85;
            }

            if (income > 4313)
            {
                taxRate = .075;
                subtract = 4313;
                add = 181;
            }
        }

        if (file == "m")
        {
            if (income <= 1726)
            {
                taxRate = .022;
                subtract = 0;
                add = 0;
            }

            if (income >= 1727 & income <= 5176)
            {
                taxRate = .033;
                subtract = 1726;
                add = 40;
            }

            if (income >= 5177 & income <= 8626)
            {
                taxRate = .062;
                subtract = 5176;
                add = 175;
            }

            if (income > 8626)
            {
                taxRate = .075;
                subtract = 8626;
                add = 390;
            }
        }

    incomeTax = ((income - subtract) * taxRate) + add;

    cout << "\nYour taxable income is " << income << endl;

    if (file == "s")
    {
        taxStatus = "Singly";
    }
    if (file == "m")
    {
        taxStatus = "Jointly";
    }
    cout << "\nand you are filing " << taxStatus << endl;

    cout << "\nThat means your income tax will be " << incomeTax << endl;

    cout << "\nWould you like to conduct another operation, y/n?\n ";
    cin >> answer;
    while (!(cin >> answer)) //get input
    {
        if (answer == "y")
        {
            goto top;
        }
        if (answer == "n")
        {
            break;
        }
        else
        {
            //if input fails, run this
            cin.clear();
            cin.sync();
            cout << "\nThat is not a correct input, please enter y/n. ";
        }
    }
    cin.ignore(80, '\n');

    system("PAUSE");

    return 0;
}

Answer 1

您在代碼中有一些小錯誤，例如if(file == "s"|| "m"這是不正確的，應該是if(file == "s" || file == "m")並且您有一個&這是一個引用，它接受變量或按位的地址。您想要的是兩個&& ，這意味着和
在這里做：

while (!(isdigit(income))) // does after cin >> income;
{
        //if input fails, run this
        cin.clear();
        cin.sync();
        cout << "\nSorry, that was not a valid number. Please enter a valid number\n ";
        cin >> income
}

while (!(file == "s" || file == "m")) //this goes after cin >> file;
{
        cin.clear();
        cin.sync();
        cout << "\nThat is not a correct input, please enter s/m\n ";
        cin >> file;
}

Answer 2

因此，我讓它不再要求兩次輸入，因此感謝您的幫助。 在以美元格式輸出收入和所得稅並在末尾選擇“ y”時返回程序的開始時，我仍然遇到問題。 有什么建議么？

int main()
{
    double income = 0; //double stores income input
    double taxRate = 0;//double stores tax rate
    double add = 0;//double stores value added
    double subtract = 0;//double stores value to be subtracted
    double incomeTax = 0;//double stores final income tax
    string taxStatus = "";//string stores status of single or joint
    string file = "";//string stores values of s or m
    string answer = "";//string stores values of y or n
    top:
    //asks user to input income value
    cout << "\nPlease enter your income to calculate your taxes\n " << endl;
    while (!(cin >> income)) //get input
    {
        if (isdigit(income) & income > 0)//if value is positive or numbers, exits loop
        {
            break;
        }

        else//if value is not valid, runs this
        {
            //if input fails, run this
            cin.clear();//clears line
            cin.sync();
            cout << "\nSorry, that was not a valid number. Please enter a valid number\n ";//asks user to input valid input
        }
    }
    cin.ignore(80, '\n');

    //asks user to enter whether filing singly or jointly
    cout << "\nIf you will be filing singly, enter 's'. If you will be filing jointly, enter 'm'\n ";
    while (!(cin >> file)) //get input
    {
        if (file == "s" || "m")//if input is valid, save and break loop
        {
            cin.ignore(80, '\n');
            break;
        }

        else//if value not valid, print message and repeat
        {
            //if input fails, run this
            cin.clear();
            cin.sync();
            cout << "\nThat is not a correct input, please enter s/m\n ";
        }
    }

        if (file == "s")//loop determines double values for single filing
        {
            if (income <= 863)//if income is under this value, use these settings
            {
                taxRate = .022;
                subtract = 0;
                add = 0;
            }

            if (income >= 864 & income <= 2588)//if income is between these values, use these settings
            {
                taxRate = .033;
                subtract = 863;
                add = 25;
            }

            if (income >= 2589 & income <= 4313)//if income is between these values, use these settings
            {
                taxRate = .062;
                subtract = 2588;
                add = 85;
            }

            if (income > 4313)//if income is above this value, use these settings
            {
                taxRate = .075;
                subtract = 4313;
                add = 181;
            }
        }

        if (file == "m")//sets double values if joint filing
        {
            if (income <= 1726)//if income is under this value, use these settings
            {
                taxRate = .022;
                subtract = 0;
                add = 0;
            }

            if (income >= 1727 & income <= 5176)//if income is between these values, use these settings
            {
                taxRate = .033;
                subtract = 1726;
                add = 40;
            }

            if (income >= 5177 & income <= 8626)//if income is between these values, use these settings
            {
                taxRate = .062;
                subtract = 5176;
                add = 175;
            }

            if (income > 8626)//if income is above this value, use these settings
            {
                taxRate = .075;
                subtract = 8626;
                add = 390;
            }
        }

    incomeTax = ((income - subtract) * taxRate) + add;//determines value of income tax

    cout << "\nYour taxable income is " << income << endl;//prints total income

    if (file == "s")//prints 'single' if 's' is selected
    {
        taxStatus = "Singly";
    }
    if (file == "m")//prints 'jointly' if 'm' selected
    {
        taxStatus = "Jointly";
    }
    cout << "\nand you are filing " << taxStatus << endl;//prints filing status

    cout << "\nThat means your income tax will be " << incomeTax << endl;//prints actual income tax

    cout << "\nWould you like to conduct another operation, y/n?\n ";//asks if user wants to do another filing
    while (!(cin >> answer)) //get input
    {
        if (answer == "y")//returns to start of program if yes
        {
            goto top;
        }
        if (answer == "n")//breaks loop if no
        {
            break;
        }
        else//if not valid answer, print message and run again
        {
            //if input fails, run this
            cin.clear();
            cin.sync();
            cout << "\nThat is not a correct input, please enter y/n. ";//asks user to try again
        }
    }
    cin.ignore(80, '\n');

    system("PAUSE");

    return 0;//ends program
}