I tried my hand at C++ client/server programs, but they were extremely difficult, even with the "best tutorial" on the Web (Beej's). I could get a basic client/server program going, but it was with "blocking sockets", and all I knew how to do was get the server to send a one-line message every time a client connected. I didn't know how to get the server to perform a particular function depending on the request of the client.
An example of what I mean is:
If the client said "letters", the server would respond with "abcdef...." and if the client sent the message "numbers", the server would respond with "1234567890".
Also no idea how to get the server to manage connections with more than one user. What do you have to do, create an array of open sockets, and then when sending a message to all, use a standard for loop to send the message to socket, socket, etc?