[rightbyte]

I tried to make Fizzbuzz on a paper when I first heard of it, and it had a bug printing fizzbuzzfizzbuzz on 15.

If you want a correct program without a compiler/computer I don't think anything is too easy. Maybe like, "make a function returning the sum of two float parameters".

[kragen]

That would just test syntax, though. Fizzbuzz tests logic. Your bug was a logic bug.

To a certain extent you can dispense with mental logic by using a compiler. But the feedback loop is much slower. Thinking your logic through before feeding it to a compiler is like looking at a map when you're driving a car; you can cut off whole branches of exploration.

Binary search is a particularly tricky logic problem in part because it's so deceptively simple. In a continuous domain it's easy to get right, but the discrete domain introduces three or four boundary cases you can easily get wrong.

But the great-great-grandparent is surely correct that many programming jobs don't require that level of thinking about program logic. Many that do, it's because the codebase is shitty, not because they're working in an inherently mentally challenging domain.

[rightbyte]

Ye I meant running it and then correcting the error.

Concerning binary search I acctually implemented that in an ECU for message sorting. It took like a whole day, including getting the outer boundries one off too big in the first test run. Funnely enough the vehicle ran fine anyway.

I would never pull that algorithm off correctly in an interview without training to, I think.

[kragen]

Take a look at the downvoted-to-0 formulation I gave upthread, then see if you can program it that way tomorrow without looking, and then think it through to see if it could possibly be wrong, and once you're satisfied it's correct, try testing it. Probably you'll never need to implement binary search yourself again, but it's a good exercise for thinking through algorithms. You can probably get it working that way in under an hour instead of a whole day.