各模块的功能：

readtxt()，读读者文件writetxt()，写读者文件addreader(reader s) ，添加读者delreader(int number)，删除读者searchreader(int number)，查找读者readerdata() ，读者数据管理readbtxt()，读图书文件writebtxt()，写图书文件addbook(libook s)，添加图书delbook(int number)，删除图书searchbook(int number)，查找图书bookdata()，图书数据管理borbook()，读者借书retbook()，读者还书main()主函数

-The function of each module: readtxt (), document readers read writetxt (), document readers to write addreader (reader s), add readers delreader (int number), delete readers searchreader (int number), to find readers readerdata (), the reader data management readbtxt (), read the book documents writebtxt (), write the book documents addbook (libook s), add books delbook (int number), delete the book searchbook (int number), to find books bookdata (), data management books borbook (), readers library retbook (), readers book main () main function