public void join(Chatter chatter)
{
for(int i=0;i<chatterNumber;i++)
if(roomChatter[i].Equals(chatter))return;
System.Console.WriteLine(chatter.getUserName() + " has join the chatroom\"" + chatroomTopic + "\"");
roomChatter[chatterNumber++]=chatter;
}
public void post(String mes,Chatter chatter)
{
System.Console.WriteLine(chatter.getUserName()+":"+mes);
}