java 面向对象demo练习

public class Demo3Test1 {

    // oop练习 使用面向对象实现一个简单的银行账户系统

    public static void main(String[] args) {

        BankAccount bank1 = new BankAccount("100001","张三",0);

        bank1.displayInfo();

        // 存款
        bank1.deposit(100);

        // 取款
        bank1.withdraw(10);

        bank1.withdraw(10000);

        bank1.displayInfo();

    }

}

class BankAccount{

    private String accountNumber; // 账号
    private String owner; // 姓名
    private double balance; // 余额

    // 构造方法
    public BankAccount(String accountNumber,String owner,double balance){

        this.accountNumber = accountNumber;
        this.owner = owner;
        this.balance = balance;

    }

    // 存款方法
    public void deposit(double num){
        this.balance = this.balance + num;
    }

    // 取款方法
    public void withdraw(double num){
        if(this.balance < num){
            System.out.println("余额不足");
            return;
        }
        this.balance = this.balance - num;
    }

    // 打印用户信息
    public void displayInfo(){
        System.out.println("账号："+this.accountNumber+",持有人："+this.owner+",余额："+this.balance);
    }

}