This is near causing dissonance for me. I'm certain I had seen a version of his where he did use recursion. Rereading, you are definitely correct that he doesn't.

I know he has program in one of his books where he uses recursion to print the contents of a tree. Maybe I was just confusing that. (Don't have my books handy.)

That said, this is definitely going to make me study those programs more. Hilarious how off I was in my memory.

(The use of goto statements like he does in the main routine cracks me up, btw. Curious to know if these made a measured difference. With Knuth, I would assume so.)