Question

当用户按Y继续时，如何清除变量的所有先前值？

现在，当用户按Y时，此代码会保留所有值的堆叠。我该怎么做才能清除以前所有变量的值？

double monthlyPayment; //Get the monthly payment from user
double balance; // formula to calculate the loan.
double interestRate; // get the interest rate from user
double interestPaid;
double total_amount_of_interest_paid;
double initialBala`enter code here`nce; // get the initial cost of the item/loan.
char continueMessage; // to continue the program.
int month = 1;
cout.setf(ios::fixed);  // 2 decimal places for decimal values.
cout.setf(ios::showpoint);
cout.precision(2);

do{

cout << "Enter the amount of the loan: "; //Getting the amount of the loan from user.


//Error checking for balance
        if(!(cin >> initialBalance) || initialBalance<= 0.0)
    {
        do
        {
            cin.clear(); //Reset the failed state
            cin.ignore(1000, '\n'); //Discards up to 1000 characters or until it reaches a new line.
            cout << "Please enter positive numbers only: ";
        }while(!(cin >> initialBalance) || initialBalance <= 0.0);
    }



cout << "Enter the interest rate per month in percentage(%): "; //Getting interest rate from user.


//Error checking for interest rate. If the value is less than 1 means user entered the value in decimal form.
if (!(cin >> interestRate) || interestRate < 1.0)
    {
      do
        {
            cin.clear();
            cin.ignore(1000, '\n');
            cout << "Please make sure you enter postive numbers and in percentage form: " ;
        }while(!(cin >> interestRate )|| interestRate <=0.0);
    }

cout << "Please enter your monthly payment: ";// Getting monthly payment from user.

//Error checking for monthly payment. Value entered must be positive numbers.
if(!(cin >> monthlyPayment) || monthlyPayment < 0.0)
    {
        do
            {
                cin.clear();
                cin.ignore(1000, '\n');
                cout << "Please enter positive numbers only: ";
            }while(!(cin >> monthlyPayment) || monthlyPayment <0.0);
    }



    balance = initialBalance;
    interestRate = interestRate/100;
    balance = balance - (monthlyPayment - (balance * (interestRate)));
    cout << "Your remaining debt on month 1 is: $"<<balance<<endl;

    while(balance > 0)
        {
            if (balance < monthlyPayment){
                balance = balance - balance; // when monthly payment more than balance means the debt is fully settled.
            }else{
                balance = balance - (monthlyPayment - (balance * (interestRate)));
            }
            month++;
            cout << "Your remaining debt on month "<<month<<" is: $" << balance <<endl;

        }
        cout << "Number of months taken to clear the debt: "<<month<<endl;

        total_amount_of_interest_paid = (monthlyPayment*month) - initialBalance;
        cout << "Total amount of interest paid over the life of the loan: "<<total_amount_of_interest_paid;

        //Ask the use whether wants to continue the program or not.
        cout << "\n\nPress 'y' or 'Y' to continue (other characters to quit): ";
        cin >> continueMessage;

}while(continueMessage == 'y' || continueMessage =='Y');










return 0;

}

Answer 1

您只需要设置一个条件语句来检查continueMessage，如果它是yes，那么continue否则break循环。

Answer 2

执行此操作的一种好方法是将大多数do循环重新组织为具有局部变量的函数：

do {
    calculateInterest();

   // Ask the user whether wants to continue the program or not.
    cout << "\n\nPress 'y' or 'Y' to continue (other characters to quit): ";
    cin >> continueMessage;

} while (continueMessage == 'y' || continueMessage =='Y');

...

void calculateInterest(void) {
    double monthlyPayment; //Get the monthly payment from user
    double balance; // formula to calculate the loan.
    double interestRate; // get the interest rate from user
    ...
}

这样，每次运行函数时都会隐式重置变量。这样做也有助于为可能需要阅读它的其他人更清楚地组织代码。

如何在do-while循环期间重置c ++中的所有值？

2 个答案: