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points by kenferry 4 hours ago | 0 comments

I know it's "too clever", but if I'm writing code no one else will ever see,

  while (i --> 0) {
      // use array[i]
  }

easy to read (if not understand), and correct!

[–] krackers 4 hours ago

Oh I remember this from the classic SO post, but it was just presented as a funny trick. I never realized that it solves the issue mentioned in the article and there is a legitimate use-case for post-decrement in the comparison itself.

https://stackoverflow.com/questions/1642028/what-is-the-oper...

[–] StilesCrisis 2 hours ago

It's just spacing. X-- > 0 and X --> 0 are the same thing in C.

[–] 1718627440 2 hours ago

There is a reason postfix is the idiomatic way in C, it is the correct choice most of the time.

[–] hirvi74 1 hour ago

Swift (Lattner) was right, imo, to exclude both.

[–] golden-face 2 hours ago

Praise to the old gods and the new, why?!

[–] cryptonector 3 hours ago

It's a well-known (ish) idiom that nobody uses. It's very entertaining though, for sure. In some circles it's known as the down-to operator.

[–] viega 4 hours ago

I always use unsigned values and do:

  while (i-- != 0) { ... }

It's more clear than the most idiomatic way, which is to drop the explicit comparison:

  while (i--) { ... }

All of it is better than the clunky old for-loop syntax.

[–] chii 3 hours ago

if `i` ever gets modified inside the loop, and skips 0 (e.g., got decremented twice when it is at 1), then you might end up with an infinite loop?

Usually, this won't happen of course, but because `i` is not declared inside a for-loop, it must have been declared outside, and thus might even look like a regular variable that could be used by some "clever" coding to multipurpose it!

In any case, it's a niche worry i have, so i usually don't do it if i know there's a for loop that would do.

[–] mtklein 4 hours ago

I don't think it's too clever at all. Notably it works with both signed and unsigned i. Frankly if I see anyone doing anything other than this, they're wrong.

[–] stephencanon 4 hours ago

Always.

(Hi Ken!)