SFML would be a good choice for C++ based game development: http://www.sfml-dev.org/
Although you should focus on learning the basics of C++ first. Also keep in mind that there are many higher level alternatives (Game Maker, Unity, ect) for game creation.
In terms of audio editing/music creation, there is the Qt framework: http://qt-project.org/
Here is a forum thread on real time audio processing: http://qt-project.org/forums/viewthread/7679
Although Qt is really good for the GUI development and not necessarily the whole sound/audio buffer editing side of things. It might be better to integrate something like STK: https://ccrma.stanford.edu/software/stk/index.html
or CLAM: http://clam-project.org/ with QT.
There are many other choices, but these are the ones that I have experience with.