I'm pretty sure the swapping is a fundamental part of the quicksort algorithm, not a mere implementation detail. That's the reason quicksort is an in-place algorithm.
Actually you're right, it is an implementation detail. The original isn’t mistaken, it’s just showing the lo-to-hi partitioning pass rather than the from-both-ends version I had in mind when I implemented quicksort before.
shame, shame, I should have double-checked before posting.
shame, shame, I should have double-checked before posting.