Given a pointer to member a within a struct, write a routine that returns a pointer to the struct?

The fundamental equation here (all arithmetic in bytes) is.

The answer is: it doesn't. It doesn't work, even if it might seem to "work" at the first sight. The "answer" makes an attempt to dereference a null pointer, which leads to undefined behavior.

So, unless your idea of "working" includes undefined behavior, that answer does not work.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.