编写C++程序完成以下功能： 实现简单电话本功能，用姓名来搜索电话号码； 用户输入姓名，程序查找并输出结果； 用户可以通过输入，添加姓名和电话号码； 用户可以删除姓名和电话号码； 电话本可以保存在指定文件中； 电话可被从指定文件中读入到内存。(Write a C++ program to complete the following functions: simple phone book function, use the name to search for phone numbers; the user name, the program to find and output; users can input, add your name and telephone number; the user can delete your name and telephone number; the telephone can be saved in the specified file; the telephone can be from the specified file read into memory.)