There's nothing for C++, but I have started a book for C:

http://c.learncodethehardway.org/

Why don't you go through what I've written so far and learn the basics of C. Doing that will give you a good understanding of the foundations of C++. While C++ is a fairly different language in a lot of ways, its backwards compatibility with C means that a lot of the same issues exist. Understanding C will then make it easier to get through C++ (or Objective-C).