Quote:
I know that it isn't possible in 5 hours :(, but wanted to try it later in holiday, so it is related to database or not?(I don't now even what is database)
Probably not: the problem is that when you tell your Socket to Listen, it does not return until it has a connection, so to support multiple users you need multiple processes - which means you need to use
fork
and then respond to the appropriate Socket when it gets a message. A database won't help you with that, it doesn't support multiple Sockets, it just stores data!
You only have three hours left, and to be honest, unless you can get the fork / sockets working in that time how you store the data is irrelevant (not to mention that learning databases isn't a five minute job - heck it'll probably take you longer than that to install a multiuser database system in the first place, never mind learning to use it as well!)
If you can work on it over the holiday, then do: get forking and sockets sorted first and don't worry about data until after that.