TBF it is not complicated but it does use the simplest form of pointer arithmetic and order of operation of (++var) or (*var++). Considering OP couldn't write a basic version of this I did not want to put pressure on him. If you can understand it as a beginner good for you! You must remember that a lot of developers struggle to learn pointers in the first place for some reason. I blame AI.

EDIT: Also I did not say this is advanced, just not beginner friendly