实现制作一个通讯录功能，还有对通讯录的增删改操作，以及对数据文件的读取和改写，该代码采用多文件的方式，分成多个模块-Making an address book function, CRUD operations on contacts, as well as the data file read and rewrite the code using the multi-file into multiple modules

利用数据库系统实现通讯录。首先要将数据库文件还原。具体应用在压缩包里有-Using the system to achieve address book. First to restore the file. Specific application in the compressed package