Question

我正在尝试在主函数的底部创建一个嵌套循环，如果用户输入“y”，程序将重复，如果“n”，该函数将返回0并停止，如果用户输入其他一些字母给出错误，重新输入选择。

如果我输入“y”，程序会重复如果我输入“n”，我什么都不会像空白一样如果我输入“e”，我会陷入无限循环

int main() 
{

    //local constants
    const string ENTER_DAYS_RENTED = "Enter the number of days rented: ";
    const string ENTER_MILES_DRIVEN = "Enter number of miles driven: ";

    //local variables
    char userCarTypeChosen;
    char anotherBill;
    int daysRented;
    int milesDriven;
    double carCharge;
    double mileageCharge;
    double tax = 0;
    double total = 0;

    do 
    {
        //call function to display program description
        displayProgramDescription();

        //calls function to validate the car choice input by user
        userCarTypeChosen = validateCarChoice();

        //if car type chosen is suv (S) then only prompt will be to enter days
        //rented, if not prompt both days rented and miles driven.
        if (userCarTypeChosen == 'S')
        {
            daysRented = validateNumEntry(ENTER_DAYS_RENTED);
            cout << endl;
        }
        else
        {   
            daysRented = validateNumEntry(ENTER_DAYS_RENTED);
            cout << endl;
            milesDriven = validateNumEntry(ENTER_MILES_DRIVEN);
            cout << endl;
        }

        //blank lines between input and output
        cout << endl << endl;

        //calls function to calculate total car charge
        carCharge = calculateTotalCarCharge(userCarTypeChosen, daysRented);

        //calls function to calculate total mileage charge
        mileageCharge = calculateTotalMileageCharge(userCarTypeChosen, 
                        daysRented, milesDriven);

        calculateBillTotal(carCharge, mileageCharge, tax, total);

        printBill (userCarTypeChosen, daysRented, milesDriven, carCharge,
        mileageCharge, tax, total);

        cout << endl;
        cout << "Calculate another bill (y/n)? ";
        cin >> anotherBill;
        anotherBill = toupper(anotherBill);
        cout << endl;

    }
        while (anotherBill == 'Y');

            if (anotherBill !='N')
            cout << "Error - Calculate another bill (y/n)?" << endl;
            cin >> anotherBill;


    return 0;
}

更新：创建了这个功能

char validateCalcNewBill()
{
    char billAgain;

    cout << "Calculate another bill (y/n)?";
    cin >> billAgain;
    cout << endl;
    billAgain = toupper(billAgain);

    while (billAgain != 'Y' && billAgain !='N')
    {
        cout<< "Error - Calculate another bill (y/n)?";
        cin >> billAgain;
        billAgain = toupper(billAgain);
    }

    return billAgain;
}

然后在主

结束时

//calls function to validate calculating a new bill
        anotherBill = validateCalcNewBill();

    }
        while (anotherBill == 'Y');

    return 0;
}

Answer 1

尝试使用while循环而不是if-else语句来捕获其他答案。

char anotherBill = 'Y';

while (anotherBill != 'N')
{
    if(anotherBill == 'Y')
    {
        cout<<"Process...\n";

        cout<<"Calculate another bill? (y/n):";
        cin>>anotherBill;
        anotherBill = toupper(anotherBill);
    }
    else
    {
        cout<<"Invalid input. Please re-enter:";
        cin>>anotherBill;
        anotherBill = toupper(anotherBill);
    }
}

使用嵌套循环基于用户输入重复的程序

1 个答案: