package banking3;

//账户

public class Account {

    private double balance;// 账户余额

    public Account(double init_balance) {

        balance = init_balance;

    }

    public double getBlance() {

        return balance;

    }

    // 存钱

    public boolean deposit(double amt) {// amt 要存的额度

        balance += amt;

        return true;

    }

    // 取钱

    public boolean withdraw(double amt) {// amt：要取得额度

        if (balance >= amt) {

            balance -= amt;

            return true;

        } else {

            System.out.println("余额不足");

            return false;

        }

    }

}

package banking3;

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 String getLastName() {

        return lastName;

    }

    public Account getAccount() {

        return account;

    }

    public void setAccount(Account acct) {

        account = acct;

    }

}

package TestBanking;

import banking3.Account;

import banking3.Customer;

public class TestBanking3 {

    public static void main(String[] args) {

        Customer customer;

        Account account;

        // Create an account that can has a 500.00 balance.

        customer = new Customer("Jane", "Smith.");

        account = new Account(500.00);

        System.out.println("Creating the customer Jane Smith.");

        // code

        customer.setAccount(account);

        System.out.println("Creating her account with a 500.00 balance.");

        // code

        // 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());

    }

}

输出结果：

Withdraw 47.62: true
余额不足
Withdraw 400.00: false
Customer [Smith., Jane] has a balance of 324.88