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| From | Ike Naar <ike@sverige.freeshell.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: What a stupid gcc! |
| Date | 2012-06-19 08:43 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <slrn3vfsju0eu7.9cu.ike@sverige.freeshell.org> (permalink) |
| References | (3 earlier) <jrkckl$fh4$1@dont-email.me> <slrn3vfsjtuk8o.oe6.andrews@sdf.lonestar.org> <jrnsqm$4me$1@dont-email.me> <slrn3vfsjtvd9m.rhm.ike@iceland.freeshell.org> <jroh87$71q$1@dont-email.me> |
On 2012-06-19, BartC <bc@freeuk.com> wrote:
> "Ike Naar" <ike@iceland.freeshell.org> wrote in message
> news:slrn3vfsjtvd9m.rhm.ike@iceland.freeshell.org...
>> On 2012-06-18, BartC <bc@freeuk.com> wrote:
>
>>> In the same way I might define int i,j,k; in preparation for any
>>> for-loops
>>> there might be.
>
>> Why don't you go one step further and declare
>> retval, temp, i, j, and k as global variables?
>
> Because it won't work?
>
> Exactly the same 'i' could be in use simultaneously in different functions.
>
> That's unlikely to be the case with a single local 'i' in a function.
>
> But you can also go too far the other way, and end up with this (modified
> from Noob's example):
>
> for (int i = 0; i < N1; ++i)
> for (int i = 0; i < N2; ++i)
> for (int i = 0; i < N3; ++i)
> do_whatever_with(i, i, i); /* ? */
Yes, that's gone too far the other way and it won't work.
In the inner loop the outer i's are hidden by the inner i.
But this is not a very good argument against declaring variables
close to where they are used. If you would declare i at the start
of the function, it would be a mess as well:
int i;
/* ... */
for (i = 0; i < N1; ++i)
for (i = 0; i < N2; ++i)
for (i = 0; i < N3; ++i)
do_whatever_with(i, i, i); /* ? */
The mess has nothing to do with the placement of the declarations,
it's a mess because, in one context, one identifier is used for
three purposes.
In
int i, j, k;
/* ... */
for (i = 0; i < N1; ++i)
for (j = 0; j < N2; ++j)
for (k = 0; k < N3; ++k)
do_whatever_with(i, j, k);
vs.
for (int i = 0; i < N1; ++i)
for (int j = 0; j < N2; ++j)
for (int k = 0; k < N3; ++k)
do_whatever_with(i, j, k);
I don't see why the first variant would be an improvement
over the second one.
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What a stupid gcc! zgene <nospam@nospam.com> - 2012-06-13 21:41 +0000
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-13 18:01 -0400
Re: What a stupid gcc! Noob <root@127.0.0.1> - 2012-06-14 13:00 +0200
Re: What a stupid gcc! Nomen Nescio <nobody@dizum.com> - 2012-06-14 14:33 +0200
Re: What a stupid gcc! Rui Maciel <rui.maciel@gmail.com> - 2012-06-14 14:46 +0100
Re: What a stupid gcc! Noob <root@127.0.0.1> - 2012-06-14 18:19 +0200
Re: What a stupid gcc! Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-06-13 18:06 -0400
Re: What a stupid gcc! jt@toerring.de (Jens Thoms Toerring) - 2012-06-13 22:19 +0000
Re: What a stupid gcc! Rui Maciel <rui.maciel@gmail.com> - 2012-06-14 09:47 +0100
Re: What a stupid gcc! Rui Maciel <rui.maciel@gmail.com> - 2012-06-14 14:37 +0100
Re: What a stupid gcc! Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-06-13 17:05 -0600
Re: What a stupid gcc! Nick Bowler <nbowler@draconx.ca> - 2012-06-14 00:09 +0000
Re: What a stupid gcc! Varun Tewari <tewari.varun@gmail.com> - 2012-06-14 03:14 -0700
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-14 06:56 -0400
Re: What a stupid gcc! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-06-17 07:18 +0000
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-17 11:47 +0100
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-17 09:31 -0400
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-18 12:34 +0100
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-18 08:18 -0400
Re: What a stupid gcc! gwowen <gwowen@gmail.com> - 2012-06-18 05:42 -0700
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-18 09:39 -0400
Re: What a stupid gcc! Rich Webb <bbew.ar@mapson.nozirev.ten> - 2012-06-18 09:06 -0400
Re: What a stupid gcc! ImpalerCore <jadill33@gmail.com> - 2012-06-18 07:18 -0700
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-19 00:13 -0700
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 11:28 +0100
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 07:30 -0400
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-20 00:16 -0700
Re: What a stupid gcc! Rui Maciel <rui.maciel@gmail.com> - 2012-06-17 15:52 +0100
Re: What a stupid gcc! Noob <root@localhost> - 2012-06-18 09:07 +0200
Re: What a stupid gcc! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-06-18 09:03 +0000
Re: What a stupid gcc! Andrew Smallshaw <andrews@sdf.lonestar.org> - 2012-06-18 16:02 +0000
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-18 19:40 +0100
Re: What a stupid gcc! Noob <root@localhost> - 2012-06-18 23:52 +0200
Re: What a stupid gcc! Ike Naar <ike@iceland.freeshell.org> - 2012-06-18 23:09 +0000
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 01:30 +0100
Re: What a stupid gcc! Ian Collins <ian-news@hotmail.com> - 2012-06-19 13:03 +1200
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 06:34 -0400
Re: What a stupid gcc! Ike Naar <ike@sverige.freeshell.org> - 2012-06-19 08:43 +0000
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 11:00 +0100
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 07:05 -0400
Re: What a stupid gcc! Ian Collins <ian-news@hotmail.com> - 2012-06-19 23:21 +1200
Re: What a stupid gcc! Ian Collins <ian-news@hotmail.com> - 2012-06-19 23:22 +1200
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-19 13:45 +0100
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 15:23 +0100
Re: What a stupid gcc! Ike Naar <ike@iceland.freeshell.org> - 2012-06-19 16:14 +0000
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 18:01 +0100
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 13:59 -0400
Re: What a stupid gcc! Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-06-19 15:29 -0600
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-19 18:22 +0100
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-19 21:13 +0100
Re: What a stupid gcc! Lew Pitcher <lpitcher@teksavvy.com> - 2012-06-19 16:27 -0400
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 16:38 -0400
Re: What a stupid gcc! Kenneth Brody <kenbrody@spamcop.net> - 2012-06-20 09:47 -0400
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-19 22:44 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-21 01:39 -0700
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-21 10:55 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-21 04:11 -0700
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-21 12:36 +0100
Re: What a stupid gcc! David Brown <david@westcontrol.removethisbit.com> - 2012-06-21 15:33 +0200
Re: What a stupid gcc! Andrew Smallshaw <andrews@sdf.lonestar.org> - 2012-06-21 14:15 +0000
Re: What a stupid gcc! Kenneth Brody <kenbrody@spamcop.net> - 2012-06-20 09:37 -0400
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-20 14:54 +0100
Re: What a stupid gcc! Kenneth Brody <kenbrody@spamcop.net> - 2012-06-20 18:19 -0400
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-21 00:13 +0100
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-21 02:09 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-21 02:05 -0700
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-21 11:49 +0100
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-21 14:24 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-22 00:38 -0700
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-22 13:37 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-21 01:57 -0700
Re: What a stupid gcc! "BartC" <bc@freeuk.com> - 2012-06-21 11:46 +0100
Re: What a stupid gcc! Kenneth Brody <kenbrody@spamcop.net> - 2012-06-21 14:37 -0400
Re: What a stupid gcc! Andrew Smallshaw <andrews@sdf.lonestar.org> - 2012-06-21 19:38 +0000
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-21 01:41 -0700
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-21 12:28 +0100
Re: What a stupid gcc! Kaz Kylheku <kaz@kylheku.com> - 2012-06-19 15:05 +0000
Re: What a stupid gcc! Ian Collins <ian-news@hotmail.com> - 2012-06-19 09:37 +1200
Re: What a stupid gcc! ImpalerCore <jadill33@gmail.com> - 2012-06-18 15:18 -0700
Re: What a stupid gcc! Paul J Gans <gansno@panix.com> - 2012-06-18 23:21 +0000
Re: What a stupid gcc! Ian Collins <ian-news@hotmail.com> - 2012-06-19 11:26 +1200
Re: What a stupid gcc! Paul J Gans <gansno@panix.com> - 2012-06-19 01:46 +0000
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 07:19 -0400
Re: What a stupid gcc! Stephen Sprunk <stephen@sprunk.org> - 2012-06-19 08:01 -0500
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 09:25 -0400
Re: What a stupid gcc! Les Cargill <lcargill99@comcast.com> - 2012-06-19 12:57 -0500
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-19 14:59 -0400
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-19 01:36 +0100
Re: What a stupid gcc! Paul J Gans <gansno@panix.com> - 2012-06-19 01:48 +0000
Re: What a stupid gcc! Les Cargill <lcargill99@comcast.com> - 2012-06-18 19:50 -0500
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-19 00:19 -0700
Re: What a stupid gcc! Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-06-19 12:56 +0100
Re: What a stupid gcc! nick_keighley_nospam@hotmail.com - 2012-06-20 00:26 -0700
Re: What a stupid gcc! James Kuyper <jameskuyper@verizon.net> - 2012-06-20 06:31 -0400
Re: What a stupid gcc! Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-06-18 00:18 -0600
Re: What a stupid gcc! Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-06-18 09:15 +0000
Re: What a stupid gcc! Kaz Kylheku <kaz@kylheku.com> - 2012-06-14 23:21 +0000
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