[jbri]

Actually, that's not the problem :)

The can't-modify-a-collection-while-enumerating-it issue only comes into play if you're actually using an enumerator (either directly, or as part of a foreach loop) - the code in the article uses a plain for loop along with indexing into the collection, and wouldn't run into the problem.

Rather, the primary "issue" is that without that "i--" at the end it only removes half the elements - after removing an element, all the following elements shift back one index, and so the very next element never gets removed.

[hasslblad]

Sorry, I should have been clearer. I was getting flashbacks to when I saw a similar problem (except in a for each loop), that's what set the alarm bells ringing in my head.

When I see nasty code like that, I tend to stop parsing it fully and sniff out the intent. I think it's a form of bad code blindness (like banner ad blindness) my brain is protecting me from all the bad code I've seen. If I fully parsed all the really bad code properly I’d become a dribbling wreck. :) So I tend to look at it at a higher level instead to stay sane.