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But you _don't_ know what it returns, because the behavior is either undefined or implementation defined, and you don't know the implementation.
But you do know that it's undefined or implementation defined. It's a "known unknown".
On a typical modern arch, there are consistent and reasonable answers: 1. 8 ( https://godbolt.org/z/Udcuj0 ) 2. 0 ( https://godbolt.org/z/kZz1YQ ) 3. -96 ( https://godbolt.org/z/1Xq_Oo ) 4. 1 ( https://godbolt.org/z/MIo0s_ ) 5. 2 ( https://godbolt.org/z/J0dsVW ) I agree, you can argue that it's unspecified, undefined, or whatever. It might not be well defined by the C specification, but none of these programs produce…
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Switch the compiler to ARM, which is as "typical modern arch" as it gets, and see for yourself.
I don't think it's surprising when you switch machine architecture and/or word sizes that you get different results. In fact for me, that's completely normal and to be expected.
Isn't there a more fundamental flaw in these questions? main() always returns an int, whether that's 4 or 8 bytes, 0 or 1 means success or failure depends on the implementation. here's a bit of a discussion https://stackoverflow.com/questions/204476/what-should-main-... Reminds me of the dumb exams some teachers would set to trick you when in school to make themselves feel superior.
tl;dr - C has some undefined behavior, if you plan on things working based on your experience with one compiler and one computer, you will be surprised.
I wonder how many C programmers have experience with writing multi platform/compiler code. I have done a lot of C and C++ but never had to port it so I would not be surprised if I had made a ton of mistakes.
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Where the author goes wrong is in assuming that somehow "I don't know" can be a final answer to these things. No, it is absolutely fucking vital that you know how the compiler will pad your structures in C. Similarly to the "what size is an int" on your architecture - on an ATmega8 this is 16 bit, but the chip can't actually do all 16 bit operations in single instructions.
I took that to be the point of the article though, that just looking at the code wasn't enough to know and you needed to go further to answer these cases for your exact use case or target platform.
So, today, using the compiler installed on your system right now, sizeof(int) = 32. Great. That means nothing, and changes nothing about whether your code is correct. You should not write code relying on it. Just like you should not measure the output of the questions on this test, and declare that you know what the answers are.
There are a few problems with the questionnaire. "I don't know" is pretty generic choice to be given/choosen. Say for example, in question 5, the statement "return i++ + ++i;" is undefined, because the value of i is read and modified twice in a single sequence point (and of course, the order of addition is unspecified), which is not allowed in C. So the answer is "Undefined." (The explanation given in the page not ac…
Somewhat related, my introductory classes involved a lot of games around pre- and post- increments and short circuiting. While I get that understanding these operations is fundamentally important, is understanding ridiculous combinations of them important? I mean, these were the basis of large portions of some quizzes and midterms. I get playing with them from a theoretical perspective, as this can literally be done…
Isn't there a more fundamental flaw in these questions? main() always returns an int, whether that's 4 or 8 bytes, 0 or 1 means success or failure depends on the implementation. here's a bit of a discussion https://stackoverflow.com/questions/204476/what-should-main-... Reminds me of the dumb exams some teachers would set to trick you when in school to make themselves feel superior.
The tone is insufferable, the test is beyond useless.