linux tcp客户端设计。有协议、socket、以及文件操作才封装。c-erery one is no1；

C语言 HTTP协议下载文件，实现断点续传，socket通讯，目前只支持ip和port方式连接，有兴趣的读者可完善域名方式。 -C language HTTP protocol to download files, to achieve HTTP, socket communication, currently only supports ip and port connected, interested readers may improve its domain name.