Ask HN: Why do functional programmers hate loops (for, while, etc.)?

Re:Ask HN: Why do functional programmers hate loops (for, wh... by lanna on Tuesday July 11, 2023 @09:54AM (#36681017)

Well, how to calculate sum from 1 to 5000 ?

Instead of looping from 1 to 5000, you compute (1 + 5000) * 5000 / 2

This is what "understand problem first" actually means

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Re:Ask HN: Why do functional programmers hate loops (for, wh... by roelschroeven on Wednesday July 12, 2023 @01:09PM (#36697897)

But now you can run into problems with integer overflow. It can be solved:

    sum(n) = is_even(n) ? n/2 * (n+1) : (n+1)/2 * n

because of one n and n+1 will always be even. But it show that unfortunately things are often not as straightforward as they first appear.

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