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From: Kaz Kylheku <643-408-1753@kylheku.com>
Newsgroups: comp.lang.c
Subject: Re: Loops (was Re: do { quit; } else { })
Date: Wed, 16 Apr 2025 01:41:29 -0000 (UTC)
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On 2025-04-15, bart <bc@freeuk.com> wrote:
> Note that C's for-loop is dumb; it merely take three expressions A B C 
> that can be completely unrelated, and arranges them into a loop:
>
>    A; while (B) {...; C}

- In this proposed arrangement, if the "continue" keyword is used in the
  loop, it will not execute C. You need:

    A; while (B) {...; contin_001: C}

  and then use "goto contin_001". The 001 is for uniqueness within
  the function, to which labels are scoped.

- the arrangement doesn't produce macros very well using the
  ordinary preprocessor. Suppose we want to create loop which
  steps by 1 from hither to yon:

    #define loop_start(A, B, C) do { A = B; while (A < C) {

    #define loop_end(A)              A++; } } while (0)

  we end up with two macros, where we have to repeat the variable.

  With the for loop we can just do

    #define loop(A, B, C) for (A = B; A < C; A++)

Good thing we have that for syntax with its compact, encapsulated
header that holds all the parts needed.

If you keep plugging away with the naked "for" without making yourself a
convenient macro, that's your problem.

-- 
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