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Groups > comp.lang.c > #21776

Re: Array sizes and const

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On 06/ 4/12 10:08 AM, Malcolm McLean wrote:
> בתאריך יום ראשון, 3 ביוני 2012 22:08:01 UTC+1, מאת Ian Collins:
>> On 06/ 4/12 02:39 AM, Malcolm McLean wrote:
>>
>> Isn't whether the function modifies its arguments one of the most
>> important things you want to see at a glance?
>>
> Usually it's obvious
>
> double mean(double *x, int N)
>
> isn't going to modify x.
>
> What you might argue is that
>
> double median(double *x, int N)

Pretty please wrap your lines!

> could reasonably sort x as a side-effect. Make it const, and you've
> documented that this isn't the case. I'd say this is sufficiently
> rare to make const non-useful as a documenting feature.

But what isn't rare is something like

const double dd[] = { 1.0, 2.0, 3.1 };

mean(dd);

Which will trigger an appropriate diagnostic.

If a function doesn't modify a parameter, declare it const.  What's so 
hard about that?

-- 
Ian Collins

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Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-02 15:43 -0500
  Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-03 08:56 +1200
  Re: Array sizes and const Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-02 16:59 -0400
    Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-02 16:35 -0500
      Re: Array sizes and const jgk@panix.com (Joe keane) - 2012-06-08 20:05 +0000
      Re: Array sizes and const jgk@panix.com (Joe keane) - 2012-06-09 21:36 +0000
    Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-02 16:43 -0500
  Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-02 14:59 -0700
    Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-02 17:12 -0500
      Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-02 18:27 -0700
        Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-02 22:27 -0500
      Re: Array sizes and const "BartC" <bc@freeuk.com> - 2012-06-03 11:24 +0100
        Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-03 13:51 -0700
          Re: Array sizes and const "BartC" <bc@freeuk.com> - 2012-06-04 12:20 +0100
            Re: Array sizes and const Jens Gustedt <jens.gustedt@loria.fr> - 2012-06-04 13:54 +0200
            Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-04 14:32 -0700
  Re: Array sizes and const Nobody <nobody@nowhere.com> - 2012-06-02 23:50 +0100
    Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-03 10:53 +1200
      Re: Array sizes and const Nobody <nobody@nowhere.com> - 2012-06-03 14:35 +0100
    Re: Array sizes and const James Kuyper <jameskuyper@verizon.net> - 2012-06-02 21:11 -0400
      Re: Array sizes and const Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-03 07:39 -0700
        Re: Array sizes and const James Kuyper <jameskuyper@verizon.net> - 2012-06-03 16:03 -0400
        Re: Array sizes and const Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-03 21:49 +0100
          Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-03 14:49 -0700
          Re: Array sizes and const Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-03 15:02 -0700
            Re: Array sizes and const Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-04 01:21 +0100
        Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 09:08 +1200
          Re: Array sizes and const Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-03 15:08 -0700
            Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 10:37 +1200
              Re: Array sizes and const "BartC" <bc@freeuk.com> - 2012-06-03 23:47 +0100
                Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 10:55 +1200
                Re: Array sizes and const Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-03 16:04 -0700
                Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 11:14 +1200
                Re: Array sizes and const "BartC" <bc@freeuk.com> - 2012-06-04 00:23 +0100
                Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 11:30 +1200
                Re: Array sizes and const "BartC" <bc@freeuk.com> - 2012-06-04 00:52 +0100
                Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 12:04 +1200
                Re: Array sizes and const Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-04 01:39 +0100
                Re: Array sizes and const Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-06-04 02:35 -0700
                Re: Array sizes and const Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-04 01:33 +0100
                Re: Array sizes and const Ian Collins <ian-news@hotmail.com> - 2012-06-04 12:35 +1200
                Re: Array sizes and const pacman@kosh.dhis.org (Alan Curry) - 2012-06-04 21:28 +0000
        Re: Array sizes and const James Kuyper <jameskuyper@verizon.net> - 2012-06-04 12:08 -0400
        Re: Array sizes and const jgk@panix.com (Joe keane) - 2012-06-04 22:49 +0000
    Re: Array sizes and const David Brown <david.brown@hesbynett.no> - 2012-06-03 15:46 -0500
  Re: Array sizes and const Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-08 02:08 -0700
    Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-08 06:45 -0500
      Re: Array sizes and const Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-08 10:49 -0700
        Re: Array sizes and const Les Cargill <lcargill99@comcast.com> - 2012-06-08 18:05 -0500
    Re: Array sizes and const Keith Thompson <kst-u@mib.org> - 2012-06-08 13:31 -0700
      Re: Array sizes and const Tim Rentsch <txr@alumni.caltech.edu> - 2012-06-08 20:30 -0700

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