超级市场中，有的时候需要保存购买者的名称、电话号码、地址信息，以方便进行送货上门、订购服务。



电话号码目录是拥有大量数据的存储库，提供有关个人和组织的信息，简易的电话号码存储系统可以采用C语言来实现，并且这些信息可以保存在磁盘文件上。



随着新订户的加入、一些老订户的删除以及其他订户数据的改变，必须经常地更新目录。除了添加、删除、修改操作外，还可以查询现有的数据。

-supermarket, sometimes necessary to preserve the purchaser's name, telephone number, address information, to facilitate door-to-door, ordering services. The telephone number directory with large data storage library, providing individual and organizational information, the telephone number of simple storage systems can be used to achieve C language, and these messages can be stored on disk documents. With the accession of new subscribers, some old subscribers and other subscribers to delete data changes, must regularly updated directory. In addition to add, delete, modify operations, but also for the existing data.