package banking4;

public class Account {

    private double balance;

    public Account(double int_balance) {

        balance = int_balance;

    }

    public double getBlance() {

        return balance;

    }

    public boolean deposit(double amt) {

        balance += amt;

        return true;

    }

    public boolean withdraw(double amt) {

        if (balance >= amt) {

            balance -= amt;

            return true;

        } else {

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

            return false;

        }

    }

}

package banking4;

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 banking4;

public class Bank {

    private Customer[] customers;// 用于存放客户的

    private int numberOfCustomers;// 记录Customer的个数

    public Bank() {

        customers = new Customer[5];

    }

    // 添加一个Customer到数组中

    public void addCustomer(String f, String l) {

        Customer cust = new Customer(f, l);

        customers[numberOfCustomers] = cust;

        numberOfCustomers++;

    }

    // 获取Customer的个数

    public int getNumberofCustomer() {

        return numberOfCustomers;

    }

    // f返回指定索引位置Customer

    public Customer getCustomer(int index) {

        return customers[index];

    }

}

package TestBanking;

/*

 * 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 banking4.*;

public class TestBanking4 {

  public static void main(String[] args) {

    Bank  bank = new Bank();

    // Add Customer Jane, Simms

   bank.addCustomer("Jane", "Simms");

    //code

    //Add Customer Owen, Bryant

   bank.addCustomer("Owen", "Bryant");

    //code

    // Add Customer Tim, Soley

   bank.addCustomer("Tim", "Soley");

    //code

    // Add Customer Maria, Soley

   bank.addCustomer("Maria", "Soley");

    //code

    for ( int i = 0; i < bank.getNumberofCustomer(); i++ ) {

      Customer customer = bank.getCustomer(i);

      System.out.println("Customer [" + (i+1) + "] is "

             + customer.getLastName()

             + ", " + customer.getFirstName());

    }

  }

}

输出结果：

Customer [1] is Simms, Jane
Customer [2] is Bryant, Owen
Customer [3] is Soley, Tim
Customer [4] is Soley, Maria