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Re: int vs. unsigned int vs. size_t

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On 4/30/2011 2:03 PM, Ian Collins wrote:
> On 05/ 1/11 05:33 AM, pozz wrote:
>> Il 30/04/2011 08:40, Steve Keller ha scritto:
>>> #define ASIZE(a) (sizeof(a) / sizeof((a)[0])
>>> int a[] = { ... };
>>>
>>> void foo(void)
>>> {
>>> int i;
>>> for (i = 0; i< ASIZE(a); i++)
>>> /* do something with a[i]. */
>>> }
>>
>> I'm reading "C Unleashed" book and I found in some listings the
>> following code:
>>
>> #define ASIZE(a) (sizeof(a) / sizeof((a)[0])
>> int a[] = { ... };
>>
>> void foo(void)
>> {
>> int i;
>> for (i = 0; i< (int) ASIZE(a); i++)
>> /* do something with a[i]. */
>> }
>
> That's pretty gross. If they are going to use an invariant of one type,
> they should use a counter of the same type and not an ugly, pointless
> and distracting cast.
>
The code evidently supported only INT_MAX sized arrays.  If there were 
any possibility of larger than that (certainly not far fetched 
nowadays), this ASIZE macro could have been asserted <= INT_MAX ahead of 
the loop.  size_t is not necessarily a good choice for a loop counter; 
the largest signed int type no larger than size_t might be useful.

-- 
Tim Prince

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int vs. unsigned int vs. size_t Steve Keller <keller@no.invalid> - 2011-04-30 08:40 +0200
  Re: int vs. unsigned int vs. size_t Tim Prince <tprince@computer.org> - 2011-04-30 09:27 -0700
    Re: int vs. unsigned int vs. size_t Tim Prince <tprince@computer.org> - 2011-04-30 12:55 -0700
    Re: int vs. unsigned int vs. size_t Ian Collins <ian-news@hotmail.com> - 2011-05-01 10:34 +1200
  Re: int vs. unsigned int vs. size_t pozz <pozzugno@gmail.com> - 2011-04-30 19:33 +0200
    Re: int vs. unsigned int vs. size_t Ian Collins <ian-news@hotmail.com> - 2011-05-01 09:03 +1200
      Re: int vs. unsigned int vs. size_t Tim Prince <tprince@computer.org> - 2011-04-30 14:34 -0700
        Re: int vs. unsigned int vs. size_t Ian Collins <ian-news@hotmail.com> - 2011-05-01 10:37 +1200
  Re: int vs. unsigned int vs. size_t Datesfat Chicks <datesfat.chicks@gmail.com> - 2011-04-30 19:41 -0400
    Re: int vs. unsigned int vs. size_t Keith Thompson <kst-u@mib.org> - 2011-04-30 17:46 -0700
      Re: int vs. unsigned int vs. size_t Datesfat Chicks <datesfat.chicks@gmail.com> - 2011-05-01 21:27 -0400
  Re: int vs. unsigned int vs. size_t Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-04-30 22:23 -0700
  Re: int vs. unsigned int vs. size_t Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-01 14:16 +0100
    Re: int vs. unsigned int vs. size_t Barry Schwarz <schwarzb@dqel.com> - 2011-05-01 10:31 -0700
    Re: int vs. unsigned int vs. size_t Keith Thompson <kst-u@mib.org> - 2011-05-01 12:25 -0700
      Re: int vs. unsigned int vs. size_t James Kuyper <jameskuyper@verizon.net> - 2011-05-01 20:00 -0400
        Re: int vs. unsigned int vs. size_t Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-02 10:17 -0700
      Re: int vs. unsigned int vs. size_t Dr Nick <3-nospam@temporary-address.org.uk> - 2011-05-02 08:37 +0100
  Re: int vs. unsigned int vs. size_t ImpalerCore <jadill33@gmail.com> - 2011-05-03 06:02 -0700
    Re: int vs. unsigned int vs. size_t Peter Nilsson <airia@acay.com.au> - 2011-05-03 15:55 -0700
    Re: int vs. unsigned int vs. size_t Luca Forlizzi <luca.forlizzi@gmail.com> - 2011-05-05 02:38 -0700
      Re: int vs. unsigned int vs. size_t ImpalerCore <jadill33@gmail.com> - 2011-05-05 06:37 -0700
        Re: int vs. unsigned int vs. size_t Angel <angel+news@spamcop.net> - 2011-05-05 16:10 +0000
        Re: int vs. unsigned int vs. size_t Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-05-05 09:35 -0700
          Re: int vs. unsigned int vs. size_t Keith Thompson <kst-u@mib.org> - 2011-05-05 11:22 -0700
            Re: int vs. unsigned int vs. size_t Peter Nilsson <airia@acay.com.au> - 2011-05-05 16:06 -0700
            Re: int vs. unsigned int vs. size_t Michael Press <rubrum@pacbell.net> - 2011-05-06 02:32 -0700
        Re: int vs. unsigned int vs. size_t Luca Forlizzi <luca.forlizzi@gmail.com> - 2011-05-07 02:42 -0700

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