This is straight from Expert C Programming book, including the diagrams. It's dishonest to recycle and present it as if it's yours with a reference mention at the very bottom. This is not a reference, it's a copy.
So it sounds like your accusation is way off-base, and you should specify that you were wrong. Maybe you were just reminded of that other book but didn't verify that the article was a copy of it?
If instead by "straight from" you mean "similar to", well, there is only a handful of ways to explain this material so of course they are going to be similar.
Please don't throw around accusations of copying lightly. I would like to see more material like this shared, not less.
no it is not. in fact, this article cites the book that you mention as one of the references.