程序主界面包含了4个功能选项，通过选择不同的选项执行不同的功能，1点对点服务端2.点对点客户端3.服务器中转服务端4.服务器中转客户端-The main program interface contains four options by selecting different options to perform different functions, a point-to-point service side (2) peer-to-peer client 3. The server tr