The best, most entertaining book I've ever read on C covered that (unless I'm misremembering, but I doubt it): Expert C Programming.
https://www.goodreads.com/book/show/198207.Expert_C_Programm...
https://www.goodreads.com/book/show/198207.Expert_C_Programm...
> There is one other convention — sometimes we repeat a key point to emphasize it. In addition, we sometimes repeat a key point to emphasize it.
One more quote and I'll stop:
> ctime() converts its argument into local time, which will vary from GMT, depending on where you are. California, where this book was written, is eight hours behind London, and several years ahead