Having some clarification about  what each mode was supposed to do at the top of file will be great ....
Unfortunately, I don't understand Cin enough for making those top comments.
Yes, one of the biggest criticisms of GG's coding style is lack of comments.  There have been a number of times when he wished he had put a comment in.  A wise man once said to him "comments are just what the programmer wished it would do not what it actually does".

Phyllis/gg