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| From | sandeep <nospam@nospam.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: I need help |
| Date | 2011-05-16 18:27 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <iqrqar$f49$1@speranza.aioe.org> (permalink) |
| References | <04ee4fd1-29ef-4640-a906-22055187c1e4@glegroupsg2000goo.googlegroups.com> <iqm0nq$7st$1@dont-email.me> <iqph2n$1vh$1@speranza.aioe.org> <iqpkhl$c51$1@dont-email.me> |
Eric Sosman writes:
> On 5/15/2011 5:37 PM, sandeep wrote:
>> Eric Sosman writes:
>>> char *space = strchr(karmarkar, ' '); if (space == NULL)
>>> printf ("No spaces\n");
>>> else
>>> printf ("First space is at position %u\n",
>>> (unsigned)(space - karmarkar));
>>
>> This could give the wrong answer on implementations where PTRDIFF_MAX>
>> UINT_MAX.
>
> Thank you so very, very much for this helpful observation,
> guaranteed to clarify matters for the O.P. Maybe I should have written
>
> printf ("First space is at position %g\n",
> (double)(space - karmarkar));
>
> ... but then I'm sure you'd point out that it might print the wrong
> answer if the first space was more than 1E37 characters
> (10000000000000000000000000000000000000 characters) into the string, and
> would very likely print only an approximate answer for many shorter
> strings. I await your enlightening disquisition on this vital matter
> with great eagerness.
You are very welcome, Eric. I would say that it is actually quite a minor
point, but it's good not to get into bad habits!
I would advise using the %td format specifier for ptrdiff_t values: it is
generally better not to use double for integer values, but instead use a
large enough integer type (or a bignum library if the basic C types are
insufficient).
In C90 there is no ptrdiff_t, so casting to (signed long int) and using %
ld may be best. I don't know if pointer expressions in C90 are allowed to
yield wider types than long int.
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I need help janus <emekamicro@gmail.com> - 2011-05-14 04:05 -0700
Re: I need help "Heinrich Wolf" <invalid@invalid.invalid> - 2011-05-14 13:30 +0200
Re: I need help "Joachim Schmitz" <jojo.nospam@schmitz-digital.de> - 2011-05-14 13:46 +0200
Re: I need help "Heinrich Wolf" <invalid@invalid.invalid> - 2011-05-14 14:20 +0200
Re: I need help Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-14 04:48 -0700
Re: I need help "Joachim Schmitz" <jojo.nospam@schmitz-digital.de> - 2011-05-14 13:39 +0200
Re: I need help "Joachim Schmitz" <jojo.nospam@schmitz-digital.de> - 2011-05-14 13:44 +0200
Re: I need help "Heinrich Wolf" <invalid@invalid.invalid> - 2011-05-14 14:23 +0200
Re: I need help "Joachim Schmitz" <jojo.nospam@schmitz-digital.de> - 2011-05-16 16:47 +0200
Re: I need help James Kuyper <jameskuyper@verizon.net> - 2011-05-14 09:14 -0400
Re: I need help "Joachim Schmitz" <jojo.nospam@schmitz-digital.de> - 2011-05-16 16:43 +0200
Re: I need help Keith Thompson <kst-u@mib.org> - 2011-05-16 08:23 -0700
Re: I need help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-05-16 23:00 +0100
Rationale for Shao Miller <sha0.miller@gmail.com> - 2011-05-16 23:40 -0500
Re: Rationale for Some of 6.7.3p9? Shao Miller <sha0.miller@gmail.com> - 2011-05-16 23:43 -0500
Re: Rationale for Some of 6.7.3p9? Heikki Kallasjoki <see@end.of.message.invalid> - 2011-05-17 06:06 +0000
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Re: Rationale for Some of 6.7.3p9? Angel <angel+news@spamcop.net> - 2011-05-17 14:03 +0000
Re: Rationale for Some of 6.7.3p9? Shao Miller <sha0.miller@gmail.com> - 2011-05-17 10:19 -0400
Re: Rationale for Ike Naar <ike@iceland.freeshell.org> - 2011-05-17 06:09 +0000
Re: Rationale for Shao Miller <sha0.miller@gmail.com> - 2011-05-17 10:20 -0400
Re: I need help Columbus sailed the ocean China Blue <chine.bleu@yahoo.com> - 2011-05-14 04:45 -0700
Re: I need help Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-14 09:39 -0400
Re: I need help sandeep <nospam@nospam.com> - 2011-05-15 21:37 +0000
Re: I need help Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-05-15 18:35 -0400
Re: I need help pete <pfiland@mindspring.com> - 2011-05-15 19:45 -0400
Re: I need help pete <pfiland@mindspring.com> - 2011-05-15 20:15 -0400
Re: I need help sandeep <nospam@nospam.com> - 2011-05-16 18:27 +0000
Re: I need help Shao Miller <sha0.miller@gmail.com> - 2011-05-16 14:45 -0400
Re: I need help Keith Thompson <kst-u@mib.org> - 2011-05-16 11:41 -0700
Re: I need help Seebs <usenet-nospam@seebs.net> - 2011-05-16 19:12 +0000
Re: I need help Keith Thompson <kst-u@mib.org> - 2011-05-16 12:30 -0700
Re: I need help Seebs <usenet-nospam@seebs.net> - 2011-05-16 20:09 +0000
Re: I need help sandeep <nospam@nospam.com> - 2011-05-16 20:35 +0000
Re: I need help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-05-16 23:22 +0100
Re: I need help David Thompson <dave.thompson2@verizon.net> - 2011-05-24 01:19 -0400
Re: I need help Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 00:19 -0700
Re: I need help Seebs <usenet-nospam@seebs.net> - 2011-05-19 14:37 +0000
Re: I need help Keith Thompson <kst-u@mib.org> - 2011-05-19 08:17 -0700
Re: I need help Seebs <usenet-nospam@seebs.net> - 2011-05-19 16:08 +0000
Re: I need help Tim Rentsch <txr@alumni.caltech.edu> - 2011-05-19 11:13 -0700
Re: I need help Keith Thompson <kst-u@mib.org> - 2011-05-16 08:12 -0700
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