Question

我写了一个小作业，在其中创建了TimeDepositAccount，并且正在创建一种方法来获取当前余额，计算利息后的新余额，然后再提取一种方法。由于某些原因，我无法将新余额打印到System.out上，因为我无法获得新余额。其次，我想对撤销方法使用局部变量，因为在我们即将进行的测试中，我们将对它们进行测试，但是我们从未在课堂上进行过测试，因此我不确定该怎么做。

    public class TimeDepositAccount {
    //instance fields
    private double currentBalance;
    private double interestRate;
    //Constructors
    public TimeDepositAccount(){}

    public TimeDepositAccount(double Balance1, double intRate){
        currentBalance = Balance1;
        interestRate = intRate;
    }
    //Methods
    public double getcurrentBalance(){
        return currentBalance;
    }

    public void newBalance(){
        currentBalance = currentBalance * (1 + (interestRate/ 100) );
    }

    public double getintRate(){
       return interestRate;
    }

    public String toString(){
        return "TimeDepositAccount[ currentBalance = "+getcurrentBalance()+", 
    interestRate = "+getintRate()+"]";
    }


    public class TimeDepositAccountTester{
    public static void main (String[] args){
        TimeDepositAccount tda = new TimeDepositAccount(10,2);
        double currentBalance = tda.getcurrentBalance();
        System.out.println(currentBalance);
        tda.newBalance();
        System.out.print(currentBalance);

    }
}

我希望输出先打印10.0，然后再打印10.2，但我两次都得到10.0。

Answer 1

您想将主要方法更改为以下内容：

public static void main (String[] args){
    TimeDepositAccount tda = new TimeDepositAccount(10,2);
    double currentBalance = tda.getcurrentBalance();
    System.out.println(currentBalance);
    tda.newBalance();
    currentBalance = tda.getcurrentBalance();
    System.out.print(currentBalance);
}

变量currentBalance存储定义时的余额。更改tda的余额不会更改currentBalance的值。因此，要更新currentBalance的值，您需要再次运行currentBalance = tda.getcurrentBalance();。

如何打印第一个余额，然后打印新余额？

1 个答案: