chip8vm in C++. UI is implemented in GLFW (http://www.glfw.org/). Get introduced to chip8 by great code club (https://github.com/greatcodeclub/chip8). The comprenhensive guide "Mastering Chip8" is here (http://mattmik.com/chip8.html).
Learnt a lot from Laurence's blog http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/ and borrowd some code from its github repo(https://github.com/eshyong/Chip-8-Emulator).
A good website to play chip8 online and check javascript implementation is at https://reu.github.io/chip8.js/.