If you are serious about learning how to write C/C++, do not go a free route. Instead, I would recommend investing money into a book. When you follow free tutorials, chances are that they won't teach you what it is useful for or don't have a method of teaching. I have been reading Stephen Prata's "C Primer Plus" and I have really enjoyed it. You can't take the free route because the author's of that content have no motivation when they right the tutorial, or they charge you like $300 a month for the same content you can get in a $60 book.