linux环境下用c++封装的ftp客户端代码，主要的功能如下：1 下载单个文件2 下载整个目录3 上传单个文件4 上传整个目录还有切换远程目录，建立远程目录，设置上传模式-The linux environment with c++ package ftp client code, the main function is as follows: 1 Download single file download entire directory upload a single file upload entire directory there to switch the remote directory to establish a remote directory, set the upload mode! ! !