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Groups > comp.lang.fortran > #73535
| From | Lynn McGuire <lynnmcguire5@gmail.com> |
|---|---|
| Newsgroups | comp.lang.fortran, comp.lang.c++ |
| Subject | Re: “Why do arrays start at 0?" |
| Date | 2022-08-27 22:40 -0500 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <teeo2r$8tl$1@gioia.aioe.org> (permalink) |
| References | <tebblf$2gpm$1@dont-email.me> <tedr4l$1cc0$1@gioia.aioe.org> <tedt6n$757$1@gioia.aioe.org> <tee5i3$cqm$4@newsreader4.netcologne.de> |
Cross-posted to 2 groups.
On 8/27/2022 5:24 PM, Thomas Koenig wrote: > Lynn McGuire <lynnmcguire5@gmail.com> schrieb: >> On 8/27/2022 2:26 PM, Fred. Zwarts wrote: >>> Op 26.aug..2022 om 22:49 schreef Lynn McGuire: >>>> “Why do arrays start at 0?" >>>> >>>> https://buttondown.email/hillelwayne/archive/why-do-arrays-start-at-0/ >>>> >>>> "It's not the reason you think. No, it's not that reason either.” >>>> >>>> My Fortran starts at one. My C++ starts at zero. This has made my >>>> life hell. >>>> >>>> Lynn >>>> >>> >>> I assumed that it was done because in C x[i] is equivalent to *(x+i). >> >> Yup. So Fortran x(i) is equivalent to *(x+i-1). > > To be more precise, x(i) is equivalent to *(x+i-lbound(x,1)) > >> Or, the x is >> subtracted from first: x--; *(x+i);. > > That's an f2c idiom, which is not valid C, AFAIK, because > the pointer would point before the actual array. While the second pointer is a bad pointer, it is not a illegal pointer. Variables can point to anywhere, they are not illegal until referenced. Otherwise, code would be crashing all over the place. If I malloc'd some space, then free'd the space, and did not NULL the pointer, that dangling pointer would crash if ever referenced (hopefully) but not if it just hangs around. I wish that C/C++ would provide some sort of pointer validation but it does not. I keep track of my pointers for that reason and validate them before using when I have some error prone code. In 850,000 lines of F77 and 30,000 lines of C/C++ code, I have suspicious pointers in several areas due to programmers suballocating malloc'd space and forgetting to nullify those suballocated pointers after freeing the allocated space. Old code, you gotta love it. Lynn
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“Why do arrays start at 0?" Lynn McGuire <lynnmcguire5@gmail.com> - 2022-08-26 15:49 -0500
Re: “Why do arrays start at 0?" Gary Scott <garylscott@sbcglobal.net> - 2022-08-26 16:56 -0500
Re: “Why do arrays start at 0?" Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-08-27 00:46 +0100
Re: “Why do arrays start at 0?" d thiebaud <thiebauddick2@aol.com> - 2022-08-26 22:29 -0400
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-26 19:34 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-26 20:34 -0700
Re: “Why do arrays start at 0?" Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-26 22:05 -0700
Re: “Why do arrays start at 0?" Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-08-27 12:06 +0100
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-26 18:24 -0700
Re: Re: “Why do arrays start at 0?" scott@slp53.sl.home (Scott Lurndal) - 2022-08-27 14:28 +0000
Re: �Why do arrays start at 0?" Charlie Roberts <croberts@gmail.com> - 2022-08-28 10:25 -0400
Re: “Why do arrays start at 0?" Louis Krupp <lkrupp@invalid.pssw.com.invalid> - 2022-08-26 16:08 -0600
Re: �Why do arrays start at 0?" Charlie Roberts <croberts@gmail.com> - 2022-08-28 10:28 -0400
Re: Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-28 16:30 +0000
Re: “Why do arrays start at 0?" Ron Shepard <nospam@nowhere.org> - 2022-08-29 02:42 -0500
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-30 17:18 +0000
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-30 12:15 -0700
Re: “Why do arrays start at 0?" Mr Flibble <flibble@reddwarf.jmc.corp> - 2022-08-27 00:44 +0100
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-26 20:31 -0700
Re: “Why do arrays start at 0?" "fiz...@gmail.com" <fiziqs@gmail.com> - 2022-08-27 01:48 -0700
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-27 02:17 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-27 09:30 +0000
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-27 10:01 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-27 22:13 +0000
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-27 22:26 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-28 06:59 +0000
Re: “Why do arrays start at 0?" Lynn McGuire <lynnmcguire5@gmail.com> - 2022-08-28 13:42 -0500
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-28 20:17 +0000
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-28 14:08 -0700
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-28 14:05 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-28 21:54 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-28 21:53 -0700
Re: “Why do arrays start at 0?" Ron Shepard <nospam@nowhere.org> - 2022-08-29 02:07 -0500
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-29 01:30 -0700
Re: “Why do arrays start at 0?" Ron Shepard <nospam@nowhere.org> - 2022-08-29 10:13 -0500
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-29 12:30 -0700
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-29 03:48 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-27 05:16 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-27 05:47 +0000
Re: “Why do arrays start at 0?" d thiebaud <thiebauddick2@aol.com> - 2022-08-27 15:19 -0400
Re: “Why do arrays start at 0?" FortranFan <parekhvs@gmail.com> - 2022-08-27 12:45 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-27 22:22 +0000
Re: “Why do arrays start at 0?" "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-08-27 21:26 +0200
Re: “Why do arrays start at 0?" Lynn McGuire <lynnmcguire5@gmail.com> - 2022-08-27 15:01 -0500
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-27 22:24 +0000
Re: “Why do arrays start at 0?" John <urbanjost@comcast.net> - 2022-08-27 19:34 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-28 01:50 -0700
Re: “Why do arrays start at 0?" Lynn McGuire <lynnmcguire5@gmail.com> - 2022-08-27 22:40 -0500
Re: “Why do arrays start at 0?" Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-27 22:07 -0700
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-27 23:04 -0700
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-28 07:50 +0000
Re: “Why do arrays start at 0?" David Brown <david.brown@hesbynett.no> - 2022-08-28 11:52 +0200
Re: “Why do arrays start at 0?" Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-28 19:43 +0300
Re: “Why do arrays start at 0?" "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-08-28 10:01 +0200
Re: “Why do arrays start at 0?" Thomas Koenig <tkoenig@netcologne.de> - 2022-08-28 08:14 +0000
Re: “Why do arrays start at 0?" Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-28 11:07 +0200
Re: “Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-28 02:55 -0700
Re: “Why do arrays start at 0?" Robin Vowels <robin.vowels@gmail.com> - 2022-08-28 05:47 -0700
Re: ???Why do arrays start at 0?" Juha Nieminen <nospam@thanks.invalid> - 2022-08-29 11:15 +0000
Re: ???Why do arrays start at 0?" gah4 <gah4@u.washington.edu> - 2022-08-29 22:59 -0700
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