I found a letter! It might be from China, shall I read it?
If you didn't get the analogy, then let me explain: You're asking us about something we have zero information on and should then give a proper answer.
And again this has nothing to do with SFML, so why don't you look for a place where you can talk about anything programming related?
If you have no idea what book to read, then get one from
this list, the books listed there are good.
