I also use the odd-even number question in my phone screen. The primary purpose I use it for is to filter out people who can't program at all, my secondary purpose is to see if they can think of using a bitwise operator when prompted for an alternate solution(s). I don't think it's worthwhile to ask for more complicated problem implementations (at least at the phone screen level) since complicated algorithms aren't what we do most of the time. So far everyone I've asked it to has passed the primary purpose, but I keep it around just in case I hit these people who supposedly have Masters or PhDs and can't do it... It's still BS in a way but I don't have a better idea to filter out people who can't program than by asking them to program something, anything.
Yeah it's secondary so I don't hold it against the ones that didn't come up with it (one person came up with an idea I hadn't considered, I like that a person can think of different ways at all, which was casting the int to string and then checking the last character), it's a minor piece of information. All else being equal I'd like to see knowledge of bitwise operations demonstrated (and I'm sad to say that at my work we occasionally have to deal with bit-level concerns thanks to some legacy database decisions...) but things are typically unequal in more important matters.
That's a fairly reasonable approach. Looking for creativity in a relatively mundane problem is probably a good thing. The bitwise operator thing, if it actually needed to be used like you say, could be more appropriate for a coding standards guide if the candidate was otherwise suited. The immediate comparison I made, though admittedly contrived, was to that of the comma operator which I just learned about. Unlike self executing anonymous functions—which I'd consider hard to understand but critical to know—, they both fall into the category of fairly obscure pieces of syntax.
