Although if you are really clueless on C++, I would strongly advise against attempting to write (graphical) games. It is like trying to learn English, but the only topic you can discuss is astrophysics.
Allegro still exists, but its really only for hobbiests that have no intention on every going 3d. I do not recommend the API. The majority of 2d game developers go toward SDL or a combination of SDL and OpenGL. How is your level of C++ competency? You'll want a firm understanding before you move into 2d development and SDLs functions can be a bit odd to work with.