本专题介绍了如何去实现一个类似QQ的聊天程序，一方面让大家可以巩固前面专题的内容，另一方面让大家更好的理解即时通信软件（腾讯QQ）的工作原理和软件协议的设计。-The topic of how to achieve a similar QQ chat program, on the one hand so that we can consolidate the contents of the previous topics, on the other hand so that we better understand the instant messaging software (Tencent QQ) works and the design of the software protocol.