Java 子类方法不'；不能正确地减去

我的任务：创建Account超类和StudentAccount子类。学生账户的不同之处在于，他们的存款可获得1美元的奖金，取款可获得2美元的费用。我重写了子类中方法的超类方法。唯一似乎不起作用的方法是我的退出法

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 $1 bonus on depositing
    @Override
    public void deposit(double amount){
       super.deposit(amount + 1);

    }


    // Students pay a $2 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();

    }
}

---

你提取的金额比金额少了2个-假设学生想提取10个，他们得到10个，但他们的余额减少了8个。每次取款你都给学生2分

你可能是说

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

---

是时候学习如何调试了。似乎不起作用不是错误描述。你能解释一下发生了什么吗？什么不起作用？

取款（金额-2）

的意思是，当你的学生想取款10美元时，银行会给他8美元。取款不会影响学生的余额。相反，学生应该有自己的余额持有人，您将在构造函数中设置余额持有人。说学生薪水然后做你在帐户上做的事。此项。学生余额-=金额；