Java基础-面向对象:Bank项目练习3

实验题目 3： 修改 withdraw 方法以返回一个布尔值，指示交易是否成功。

实验目的： 使用有返回值的方法。

提 示：

1． 修改 Account 类

a. 修改 deposit 方法返回 true（意味所有存款是成功的）。

b. 修改 withdraw 方法来检查提款数目是否大于余额。如果amt小于

balance, 则从余额中扣除提款数目并返回 true，否则余额不变返回

false。

2． 在 exercise3 主目录编译并运行 TestBanking 程序，将看到下列输出;

Creating the customer Jane Smith.

Creating her account with a 500.00 balance.

Withdraw 150.00: true

Deposit 22.50: true

Withdraw 47.62: true

Withdraw 400.00: false

Customer [Smith, Jane] has a balance of 324.88

package com.troubleshooting.bank3;

//定义一个账户
public class Account {
    // 账户余额
    private double balance;

    public Account(double init_balance) {
        balance = init_balance;
    }

    // 获取账户余额
    public double getBlance() {
        return balance;
    }

    public void setBalance(double balance) {
        this.balance = balance;
    }

    // 存钱
    // amt存钱的额度
    public boolean deposit(double amt) {
        balance += amt;
        return true;
    }

    // 取钱
    // amt取钱的额度
    public boolean withdraw(double amt) {
        if (balance >= amt) {
            balance -= amt;
            return true;
        } else {
            System.out.println("余额不足！");
            return false;
        }
    }
}

package com.troubleshooting.bank3;

public class Customer {

    private String firstName;
    private String lastName;
    private Account account;

    public Customer(String f, String l) {
        firstName = f;
        lastName = l;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public Account getAccount() {
        return account;
    }

    public void setAccount(Account account) {
        this.account = account;
    }

}

package com.troubleshooting.testbank1;
/*
 * This class creates the program to test the banking classes.
 * It creates a new Bank, sets the Customer (with an initial balance),
 * and performs a series of transactions with the Account object.
 */

import com.troubleshooting.bank3.Customer;
import com.troubleshooting.bank3.Account;

public class TestBanking3 {

  public static void main(String[] args) {
    Customer customer;
    Account  account;

    // Create an account that can has a 500.00 balance.
    account = new Account(500.00);
    System.out.println("Creating the customer Jane Smith.");
    //code
    customer = new Customer("Jane", "Smith");
    System.out.println("Creating her account with a 500.00 balance.");

    //code
    customer.setAccount(account);
    account = customer.getAccount();
    // Perform some account transactions
    System.out.println("Withdraw 150.00: " + account.withdraw(150.00));
    System.out.println("Deposit 22.50: " + account.deposit(22.50));
    System.out.println("Withdraw 47.62: " + account.withdraw(47.62));
    System.out.println("Withdraw 400.00: " + account.withdraw(400.00));

    // Print out the final account balance
    System.out.println("Customer [" + customer.getLastName()
         + ", " + customer.getFirstName()
         + "] has a balance of " + account.getBlance());
  }
}

显示结果：
Creating the customer Jane Smith.
Creating her account with a 500.00 balance.
Withdraw 150.00: true
Deposit 22.50: true
Withdraw 47.62: true
余额不足！
Withdraw 400.00: false
Customer [Smith, Jane] has a balance of 324.88