It depends what platform you are programming on. C++ itself doesn't have the same sort of library that Java or C# have. That sort of functionality is traditionally supplied by the operating system. I suggest you learn C++ from a book (I like C++ Primer by Lippman but it may be a bit slow as its aimed at beginners) and then head to MSDN if you are programming on Windows. There are APIs for networking, XML parsing, encryption, just about everything you need. They are just tied to the OS instead of the language itself.
I don't know the equivalent resources for Linux or the Mac but I'm sure someone can supply them.
