学生成绩管理

使用图形用户界面。当输入给定的卡号和密码（初始卡号和密码为123456）时，系统能登录ATM柜员机系统，用户可以按照以下规则进行：

1、查询余额：初始余额为10000元

2、ATM取款：每次取款金额为正数，总额不超过5000元，支取金额不允许透支。

3、ATM存款：不能出现负存款。

4、修改密码：新密码长度不小于6位，不允许出现6位完全相同的情况，只有旧密码正确，新密码符合要求，且两次输入相同的情况下才可以成功修改密码

-Student performance management and use of graphical user interface. When you enter a given card number and password (the initial number and password is 123456), the system can log on ATM ATM system, the user can follow the following rules: 1, query balance: the initial balance of 10,000 yuan 2, ATM withdrawals : the amount of each withdrawal is a positive number, the total amount does not exceed 5,000 yuan in the amount of withdrawal does not allow overdrafts. 3, ATM deposits: Deposits can not be negative. 4, Change Password: The new password length is not less than 6, does not allow for six exactly the same situation, only the old password is correct, the new password meets the requirements, and the two enter the same circumstances can successfully change your password