A simple chat program using TCP, it includes a server and multiple clients, clients talk to each other through the server.
It supports functionalities like sending messages, broadcasting messages, requiring the user's list.

To use this program:
make (compile the files)
./server [port-number] (start the server)
./cclient handle_name server-name server-port (on other terminal, start the client)

For example, if I want to start the server on account unix1 using the port 55555, the command will be "./server 55555".
Then, if on account unix2 I want to start the first client, and give it a name called client1, 
the command is "./cclient client1 unix1 55555". Using the same way, on account unix3 I create the second client, 
the command is "./cclient client2 unix1 55555". So these two clients can talk to each other.

To make these clients talking to each other, the commands are:

%M [num-handles] destination-handles [destination-handles] [text]
    For example, client1 want to talk to client2, "%M 1 client2 How are you?"

%B [text]
    This will broadcast the text to all other clients, "%B Hello!"

%L
    This will print out the list of all clients

%E
    This will exit the current client