当我们首次去银行开帐户时，银行卡里存放入一个初始金额（5元或10元）。在存折上有银行帐号和帐户余额。当向指定的银行帐号存钱时，余额会增加；当在指定的银行帐号取钱时，余额会减少。银行帐户一经开户，除非用户取消，否则银行应该保留用户的帐号以及和帐号对应的身份信息（这个程序中不考虑用户身份的认证）。将每个用户的帐号上的重要信息存放在一个文件名为inout.txt的文件中。为了可以随时随地查询用户的帐户里的余额信息，将帐户中的相关信息以二进制格式读写文件。经过分析知道，要对用户的帐户信息进行通用（添加、修改、删除和显示等）的操作。-When we first when to open a bank account, bank card into an initial amount of storage (5 yuan or 10 million). In the book there are bank accounts and the account balance. When the bank account number to the designated deposit, the balance will increase　When money designated bank account, the balance will be reduced. Upon opening a bank account, unless the user cancels, or the user s bank account should be retained as well as the identity of the corresponding account information (this procedure does not consider user authentication). Each user s account of the important information is stored in a file called inout.txt document. At any time in order to query the user s account balance information, account information in binary format to read and write files. The analysis know that the user account information in general (add, modify, delete and display, etc.) operation.