一个在线考试系统，客户端安装一个软件，登录之后，服务器自动生成一套试题，然后传递给客户端，考生答题完毕后，点击交卷，服务器可以开始判卷-An online examination system, install a client software, login, the server automatically generates a set of questions, and then passed to the client, after the candidates answer, cli