使用图形用户界面。当输入给定的卡号和密码（初始卡号为123456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：

查询余额：初始余额为50000元

　　ATM取款：每次取款金额为100的倍数，总额不超过5000元，支取金额不允许透支。

ATM存款：不能出现负存款。

　　修改密码：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。

-Using a graphical user interface. When you enter a given number and password (initial card number is 123456 and the password is 123456), the system can log in an ATM system, the user can follow the following rules: check your balance: Initial balance of 50,000 yuan ATM withdrawals: the amount of each withdrawal multiples of 100, totaling no more than 5,000 yuan, the amount of withdrawal does not allow overdrafts. ATM Deposits: Deposits can not be negative. Change Password: Only the old password is correct, the new password meets the requirements, and enter the same case twice before they can successfully change the password.