Hi Am 14.02.22 um 11:38 schrieb Andy Shevchenko:
On Mon, Feb 14, 2022 at 10:03:53AM +0100, Thomas Zimmermann wrote:Am 11.02.22 um 16:41 schrieb Andy Shevchenko:...IMO *always* prefer a for loop over while or do-while. The for (i = 0; i < N; i++) is such a strong paradigm in C. You instantly know how many times you're going to loop, at a glance. Not so with with the alternatives, which should be used sparingly.while () {} _is_ a paradigm, for-loop is syntax sugar on top of it.Naw, that's not true.In the section 3.5 "Loops - While and For" in "The C Programming Language" 2nd by K&R, the authors said:
Year of publication: 1988 . It's not the most up-to-date reference for C programming.
The for statement ... is equivalent to ... while..." They said that for is equivalent to while, and not otherwise.
Even leaving readability aside, it's not equivalent. You can declare variables as part of the for statement. (I know it's not the kernel's style.) Also, 'continue' statements are not well-suited in for loops, because it's non-obvious if the loop's update statement is being executed. (It isn't.)
Also, syntax sugar by definition declares something that can be written as a single line of code, which usually is done using more (not always).
The discussion has entered the phase of hair splitting. Good. Best regards Thomas
An idiomatic for loop, such as for (i = ...; i < N; ++i), is such a strong pattern that it's way better than the corresponding while loop.And yes, the do-while suggested above is buggy, and you actually need to stop and think to see why.It depends if pixels can be 0 or not and if it's not, then does it contain last or number. The do {} while (--pixels); might be buggy iff pixels may be 0.
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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