I remember this appearing on an exam in my C class back in '89 or so. It was basically "What does this code output...", and had "if (a = 3)" instead of "if (a == 3)". Thing is, I recognized the mistake, and though the instructor made a typo. So I answered based on what I thought the instruct had meant. Of course I got the question wrong. (I was fairly cocky back then, and normally I would have answered the question at face value just to "be that way", but I was trying to break that bad habit and it ended up back-firing on me anyway).