修改withdraw 方法
练习目标-使用有返回值的方法:在本练习里,将修改withdraw方法以返回一个布尔值来指示交易是否成功。
任务
1. 修改Account类
- 修改deposit 方法返回true(意味所有存款是成功的)。
- 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exercise2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 banking; public class Account { //成员属性 private double balance ;//余额 // 无参构造 public Account() { } // 有参构造 public Account(double balance) { this.balance = balance; } // set get public double getBalance() { return balance; } public void setBalance(double balance) { this.balance = balance; } public boolean withdraw1( double amt ) { if(amt>0&&amt<balance==true) { balance -= amt ; System.out.print("Withdraw " + amt+" : "); return true ; } else { System.out.print("Withdraw " + amt+" : "); return false ; } } public boolean deposit1( double amt ) { if(amt<0) { System.out.print("Deposit " + amt+" : " ); return false ; } else { balance += amt ; System.out.print("Deposit " + amt +" : "); return true ; } } }
Customer cr1 = new Customer( ) ; cr1.setFirstName("Jane"); cr1.setLastName("Smith"); cr1.setBalance(500); System.out.println("Creating the customer "+cr1.getFirstName() +" "+cr1.getLastName()); System.out.println("Creating her account with a " +cr1.getBalance()+" balance"); System.out.println(cr1.withdraw1(150) ); System.out.println(cr1.deposit1(22.5)); System.out.println(cr1.withdraw1(47.62)); System.out.println(cr1.withdraw1(400)); System.out.println("Customer "+cr1.getLastName()+" "+cr1.getFirstName()+ " has a balance of "+cr1.getBalance());
时间: 2024-11-02 18:01:11