使用c语言编写的ftp客户端程序。实现的命令有：open，usr，pwd，cd，ls/dir，get，put，delete，mkdir，help/?，quit。在linux下编译执行。-Using the c language of the ftp client program. Implemented commands: open, usr, pwd, cd, ls/dir, get, put, delete, mkdir, help /?, Quit. Compiled in the li