储蓄等级的借方和贷方

Question

我有一个抽象类，有4种记入，借记，存款和取款的方法。我不知道如何设置贷记和借记账户的方法，因为我认为这与存款和取款相同，但我不相信。她已经提供了一个测试工具，所以我只需要设置课程。这是抽象类

  abstract public class Account implements PostInterest
    {
      private String fName;
      private String lName;
      private String nbrSSN;
      private char acctStatus = 'A';
      private double balance = 0.0;

      //five-argument constructor
      public Account(String first, String last, String ssn, char status, double begBalance)
      {
        setName(first);
        setLast(last);
        setSSN(ssn);
        setStatus(status);
        setBalance(begBalance);
      }

      public Account(String first, String last, String ssn)
      {
         setName(first);
        setLast(last);
        setSSN(ssn);
      }

      public void setName(String first)
      {
        fName = first;
      }

      public String getName()
      {
        return fName;
      }

      public void setLast(String last)
      {
        lName = last;
      }

      public String getLast()
      {
        return lName;
      }

      public void setSSN(String ssn)
      {
        nbrSSN = ssn;
      }

      public String getSSN()
      {
        return nbrSSN;
      }

      public void setStatus(char status)
      {
        acctStatus = status;
      }

      public char getStatus()
      {
        return acctStatus;
      }

      public void setBalance(double begBalance)
      {
        balance = begBalance;
      }

      public double getBalance()
      {
        return balance;
      }



      public abstract void debitAccount(double amount);

      public abstract void creditAccount(double amount);

      public abstract void deposit(double amount);

      public abstract void withdraw(double amount);




    }

这是我节省的课程之一。我还需要其他一些课程，但如果有意义的话，我会在设置信用卡和借记卡时与存款和取款相比存在差异。

    public class Savings extends Account
    {
      private double intRate;

      public Savings(String first, String last, String ssn, double begBalance, double rate)
      {
        super(first, last, ssn, begBalance);

        setRate(rate);

      }

      Public Savings(String first, String last, String ssn, double rate)
      {
        super(first, last, ssn);

        setRate(rate);

      }


      public void setRate(double rate)
      {
        intRate = rate;
      }

      public double getRate()
      {
        return intRate;
      }


      @Override
      public void debitAccount(double amount)
      {

      }

      @Override
      public void creditAccount(double amount)
      {

      }

      @Override
      public void deposit(double amount)
      {
      balance += amount;
      }

      @Override
      public void withdraw(double amount)
      {
        if(amount > balance)
        {
          balance = -1;
        }
        else
        {
          balance -= amount;
        }

        }



  @Override
  public void postMonthly()
  {
  ((intRate/12)* balance);
  }
}

我还没有设置postMonthly方法，但她希望我们根据当前余额和intRate计算月份的利息，并调用creditAcct（），传递利息计算结果，这让我有点困惑。任何帮助将不胜感激！