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| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Two options of a program to find a track in the list |
| Date | 2015-10-23 17:25 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <n0djdk$sim$1@dont-email.me> (permalink) |
| References | (2 earlier) <46021cd2-aee9-41f6-8038-65bbb362f502@googlegroups.com> <n0csmd$1qp$1@dont-email.me> <n0d8gj$cf8$1@dont-email.me> <n0dgkn$g2n$1@dont-email.me> <n0dho5$l94$1@dont-email.me> |
On 23/10/15 16:57, Eric Sosman wrote: > On 10/23/2015 10:38 AM, Richard Heathfield wrote: >> On 23/10/15 13:19, Bartc wrote: >>> On 23/10/2015 09:57, Richard Heathfield wrote: >>>> On 23/10/15 09:16, Alla _ wrote: >>> >>>>> I. sizeof(all_tracks) / sizeof(all_tracks[0]); >>>> >>>> The parentheses are superfluous and serve no purpose at all. >>>> >>>> sizeof all_tracks / sizeof all_tracks[0] >>>> >>>> works just fine. >>> >>> Yet sometimes the parentheses are needed. >> >> Almost never, in fact. You only ever need them when using a >> parenthesised type as an operand, and that's almost always a bad idea. >> >>> How to remember when you need >>> them and when you don't? Simplest is to just use them all the time. >> >> How do you remember when you need to have a Christmas tree in your >> living room? Simplest is to just have one there all the time. >> >> There is a good reason *not* to use the parentheses, which is that >> omitting them acts to reinforce the fact that sizeof is an operator, not >> a function, something that is otherwise quite easy to forget. > > Why is the distinction important enough to be worth flaunting? > Would forgetting the distinction (whether easily or by a deliberate > act of will) have tragic consequences? I would go further and say that if you are using sizeof in a way that does not work as though it were a sortof-function, or it is not obvious what it is doing despite the parentheses, then your code is probably unclear in the first place. About the only think I can think of where it really matters that sizeof is not a function is if the operand has side effects. "sizeof(a++)" does not increment "a" in the way "foo(a++)" does. Writing either "sizeof(a++)" or "sizeof a++" is, IHMO, bad code in the first place. I would even question "foo(a++)" in most cases, but I expect opinion will differ on that one. Incidentally, MISRA (the C coding standard mandated by the automotive industry in Europe, amongst others) insists that sizeof has parenthesis - it also insists on parenthesis to show operator precedence. I don't always agree with MISRA, but I agree on that one. > > Sometimes I use the parentheses, sometimes I don't -- I go with > whatever seems more readable in the context of the moment. I also > sometimes use unnecessary parentheses elsewhere, like `x << (y + z)' > or `(a && b) || c'. The parentheses are unnecessary, but so, I think, > is chastisement for using them. In those two cases, I would immediately reject code that did not have those parentheses - they may be unnecessary to a C compiler, but they are very necessary to clear coding with minimal risk of errors. > > Heck, I go so far as to insert large amounts of white space in > my code, even though it's utterly unnecessary! Gonna sue me? >
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Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-22 11:30 -0700
Re: Two options of a program to find a track in the list Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-22 14:44 -0400
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 01:16 -0700
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 01:22 -0700
Re: Two options of a program to find a track in the list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-23 10:52 +0100
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 09:57 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 02:35 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 10:59 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 03:42 -0700
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 03:47 -0700
Re: Two options of a program to find a track in the list Barry Schwarz <schwarzb@dqel.com> - 2015-10-23 11:02 -0700
Re: Two options of a program to find a track in the list Geoff <geoff@invalid.invalid> - 2015-10-23 11:24 -0700
Re: Two options of a program to find a track in the list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-23 10:39 +0100
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 11:03 +0100
Re: Two options of a program to find a track in the list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-23 11:21 +0100
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 11:36 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 02:42 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 11:10 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 03:24 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 11:45 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 09:00 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 17:16 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 09:47 -0700
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 13:19 +0100
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 15:38 +0100
Re: Two options of a program to find a track in the list Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-23 10:57 -0400
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 15:59 +0100
Re: Two options of a program to find a track in the list David Brown <david.brown@hesbynett.no> - 2015-10-23 17:25 +0200
Re: Two options of a program to find a track in the list Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-23 11:55 -0400
Re: Two options of a program to find a track in the list Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-10-23 10:45 -0600
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 16:55 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 17:21 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 17:23 +0100
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 12:58 -0700
Re: Two options of a program to find a track in the list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-23 02:19 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 10:28 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 11:12 +0100
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 13:42 -0700
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 22:14 +0100
Re: Two options of a program to find a track in the list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-23 22:28 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 22:47 +0100
Re: Two options of a program to find a track in the list Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-23 23:21 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-24 01:37 +0100
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 14:52 -0700
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-23 23:06 +0100
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 16:39 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-24 21:26 +0100
Re: Two options of a program to find a track in the list Bartc <bc@freeuk.com> - 2015-10-24 22:28 +0100
Re: Two options of a program to find a track in the list Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-24 15:26 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-24 23:44 +0100
Re: Two options of a program to find a track in the list Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-23 09:03 -0400
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 09:10 -0700
Re: Two options of a program to find a track in the list Geoff <geoff@invalid.invalid> - 2015-10-23 11:21 -0700
Re: Two options of a program to find a track in the list Barry Schwarz <schwarzb@dqel.com> - 2015-10-22 14:50 -0700
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 01:25 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 10:00 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 01:36 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 10:04 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 03:58 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 12:07 +0100
Re: Two options of a program to find a track in the list Alla _ <modelling.data@gmail.com> - 2015-10-23 09:28 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-23 18:04 +0100
Re: Two options of a program to find a track in the list Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-23 13:31 -0400
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-24 21:21 +0100
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 13:45 -0700
Re: Two options of a program to find a track in the list Ian Collins <ian-news@hotmail.com> - 2015-10-24 10:32 +1300
Re: Two options of a program to find a track in the list Keith Thompson <kst-u@mib.org> - 2015-10-23 15:33 -0700
Re: Two options of a program to find a track in the list Richard Heathfield <rjh@cpax.org.uk> - 2015-10-24 21:24 +0100
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