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Groups > comp.lang.fortran > #73564
| From | Juha Nieminen <nospam@thanks.invalid> |
|---|---|
| Newsgroups | comp.lang.fortran, comp.lang.c++ |
| Subject | Re: ???Why do arrays start at 0?" |
| Date | 2022-08-29 11:15 +0000 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <tei759$19qc$1@gioia.aioe.org> (permalink) |
| References | <tebblf$2gpm$1@dont-email.me> |
Cross-posted to 2 groups.
In comp.lang.c++ Lynn McGuire <lynnmcguire5@gmail.com> wrote: > ???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. I don't know if it's the *original* reason, but I would assume that at least in C one of the main reasons is the principle of maximum efficiency. In many processor architectures the concept of "array" exists, at least when it comes to values of the register sizes (ie. usually 1-byte, 2-byte, 4-byte and 8-byte elements, the last one at least on 64-bit architectures). Prominently the concept of an indexable array exists in the x86 architecture. (I don't remember now if it also exists in the ARM architecture, but I would guess so.) Generally when a processor architecture supports the concept of an "array", it does so by having instructions that take (at least) two registers as the input or the output parameter: A base address, and an offset. The memory location of the element is calculated by adding those two. (The number of bytes that an offset of 1 jumps depends on the instruction, and thus multi-byte elements are supported.) Thus zero-indexing is extraordinarily natural in processor architectures: The "index" is actually an offset. It's a value you add to the base address in order to get to the location you want. Thus, the first element is at index/offset 0. Since that's the case, the most optimal way to handle low-level arrays is to have 0-based indexing in the programming language as well. That way you don't need to be subtracting 1 from the index every time an array is accessed (or you don't need an extraneous unused element at the beginning of the array, consuming memory for no reason). Also, since C supports pointer arithmetic, many operations become simpler. Such as getting the index of an element when what you have is a pointer to it (and the pointer to the start of the array).
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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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