It’s almost like every thing you see people code on the Raspberry Pi is written in Python. Don’t get me wrong I love me some Python but sometimes you have to step your game up. Hack Your Mind has you covered. They’ve put together a Open Source C++ library for working with the GPIO pins on the Pi.
The video is actually a playlist of some of the functionality they have right now. So the basics like controlling the GPIO states, doing matrix keypads, multiple display types, stepper control, sensors, etc. If you want to get some speed out of your Pi and ditch the Python scripts, check out rpi-hw.