银行帐户计划，更改余额

Question

我正在尝试取款后余额要更改，但仍为10.00。 我不知道如何在SavingsAccount中正确应用一种方法来更改它。 我尝试过但没有成功。

import java.util.Date;

public class Account {
    private int id;
    private double balance;
    private double annualInterestRate;
    private Date dateCreated;
    private double monthlyInterestRate;

    public Account() {
        id = 0;
        balance = 0;
        annualInterestRate = 0;
    }

    public Account(int iD, double balancE) {
        id = iD;
        balance = balancE;
    }

    public void setID(int iD) {
        id = iD;
    }

    public int getID() {
        return (id);
    }

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

    public double getBalance() {
        return (balance);
    }

    public void setAnnualInterestRate(double AIR) {
        annualInterestRate = AIR;
    }

    public double getAnnualInterestRate() {
        return (annualInterestRate);
    }

    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }

    public double getMonthlyInterestRate() {
        return ((annualInterestRate / 100) / 12);
    }

    public double getMonthlyInterest() {
        return (balance * monthlyInterestRate);
    }

    public void withdraw(double ammount) {
        balance = balance - ammount;
    }

    public void deposit(double ammount) {
        balance = balance + ammount;
    }
}

public class SavingsAccount extends Account {
    public SavingsAccount(int iD, double balancE) {
        super(iD, balancE);
    }

    @Override
    public void withdraw(double amount) {
        if (amount > getBalance()) {
            System.out.println("Current Balance: " + getBalance() 
                    + "\nThe             withdrawal  cannot be made due to insufficient  funds.");
        }

    }
}



public class Test extends Account {

    public static void main(String[] args) {
        SavingsAccount a1 = new SavingsAccount(1122, 10.00);
        a1.withdraw(5.00);
        a1.deposit(00.00);
        a1.setAnnualInterestRate(4.5);
        Date dat = new Date();

        System.out.println("Balance: " + a1.getBalance() + 
                "\nMonthly Interest: " + a1.getMonthlyInterest() + 
                "\nDate Created: " + dat);

    }
}

Answer 1

尝试：

public void deposit(double ammount) {
        balance = balance + ammount;
        setBalance(balance);
    }

您应该在提款和余额结束时调用setBalance，并传入新的余额金额。

Answer 2

在withdraw() ，您仅检查提款金额大于余额的情况，然后打印一条消息。 您还必须处理合法的提款金额。

@Override
public void withdraw(double amount) {
    if (amount > getBalance()) {
        System.out.println("Current Balance: " + getBalance() 
                + "\nThe             withdrawal  cannot be made due to insufficient  funds.");
    } else {
        super.withdraw(amount);
    }

}

Answer 3

您必须在public void withdraw方法中使用setBalance方法。 像这样：

public void withdraw(double amount) {
        if (amount > getBalance()) {
            System.out.println("Current Balance: " + getBalance() + "\nThewithdrawal  cannot be made due to insufficient  funds.");
        }
         else
         {
            setBalance(getBalance() - amount);
         }

现在，它将为您的balance变量设置新值，因为如果您提款，您的帐户中将有balance-amount 。

希望对您有帮助！