子类方法不能正确减去

Question

我的任务：创建一个 Account super class 和一个 StudentAccount subclass。 StudentAccount 的不同之处在于，他们存款可获得 1 美元的奖金，但提款则需支付 2 美元的费用。我为 subclass 中的方法覆盖了 superclass 方法。唯一似乎不起作用的方法是我的提款方法。

public class BankTester
{
    public static void main(String[] args)
    {
        Account deez = new Account("Bob", 10.0);
        Account jeez = new StudentAccount("Bobby", 10.0);

        jeez.withdrawal(2.0);
        System.out.println(jeez);

        deez.withdrawal(2.0);
        System.out.println(deez);

    }
}


public class Account
{
private String name;
private double balance;

// Initialize values in constructor
public Account(String clientName, double openingBal){
   name = clientName;
   balance = openingBal;
}

// Complete the accessor method
public double getBalance(){
    return balance;

}

// Add amount to balance
public void deposit(double amount){
   balance += amount;

}

// Subtract amount from balance
public void withdrawal(double amount){
    balance -= amount;

}

// Should read: Regular account with a balance of $__.__
public String toString(){
   return "Regular account with a balance of $" + balance;

}
}


public class StudentAccount extends Account
{
   // Complete this class with Override methods.   

    public StudentAccount(String studentName, double 
openingBal){
        super(studentName, openingBal);
    }

    // Students get a  bonus on depositing
    @Override
    public void deposit(double amount){
       super.deposit(amount + 1);

    }


    // Students pay a  fee for withdrawing
    @Override
    public void withdrawal(double amount){
        super.withdrawal(amount - 2);   
    }

    // toString() Should read: Student account with a 
balance of $__.__
    @Override
    public String toString(){
       return "Student account with a balance of $" + 
super.getBalance();

    }
}

Answer 1

您提款比金额少 2 - 假设学生想提款 10，他们得到 10，但他们的余额减少了 8。您给学生一个 credit 每次提款 2。

你的意思可能是

public void withdrawal(double amount){
    super.withdrawal(amount + 2);   
}

子类方法不能正确减去

Subclass method doesn't subtract correctly

java

superclass