Merge branch 'master' of https://github.com/PreslavMihaylov/programming-principles-and-practice-using-cpp

Initial commit

Added the final chapter from the ppap book

Added chapter 26 exercises

added chapter 25 exercises

added chapter 23

added chapter 21

added chapter 20 exercises

added chapter 19 exercises

Added self assignment check for skip list

added chapter 18. Merry christmas btw

Added chapter 17

added chapter 16

removed all objs directories in repo

removed all exe files from the repo