C Programming: difference between ++i and i=i+1 from an assembler point of view?

Question

This was an interview question. I said they were the same, but this was adjudged an incorrect response. From the assembler point of view, is there any imaginable difference? I h

Answer 1

To defend the interviewer, context is everything. What is the type of i? Are we talking C or C++ (or some other C like language)? Were you given:

++i;
i = i + 1;

or was there more context?

If I had been asked this, my first response would've been "is i volatile?" If the answer is yes, then the difference is huge. If not, the difference is small and semantic, but pragmatically none. The proof of that is the difference in parse tree, and the ultimate meaning of the subtrees generated.

So it sounds like you got the pragmatic side right, but the semantic/critical thought side wrong.

To attack the interviewer (without context), I'd have to wonder what the purpose of the question was. If I asked the question, I'd want to use it to find out if the candidate knew subtle semantic differences, how to generate a parse tree, how to think critically and so on and so forth. I typically ask a C question of my interviewees that nearly every candidate gets wrong - and that's by design. I actually don't care about the answer to the question, I care about the journey that I will be taking with the candidate to reach understanding, which tells me far more about than right/wrong on a trivia question.