I am just trying to learn myself so take this with a grain of salt but I have found the github of Antirez:(https://github.com/antirez) - the author of Redis - to be an amazing resource. The code is incredibly well documented and to my eyes pretty well written. A good place to start I think is Kilo:(https://github.com/antirez/kilo/blob/master/kilo.c) - a 1000 line text editor with no dependencies.