From: michael@kjorling.se (Michael Kjörling)
Subject: [TUHS] Array index history
Date: Wed, 7 Jun 2017 13:50:04 +0000 [thread overview]
Message-ID: <20170607135004.GB7802@yeono.kjorling.se> (raw)
In-Reply-To: <201706071320.v57DKhmJ026303@freefriends.org>
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On 7 Jun 2017 07:20 -0600, from arnold at skeeve.com:
> Basically, until C came along, the standard practice was for indices
> to start at 1. Certainly Fortran and Pascal did it that way. I suspect
> that all the Algol family languages did too, but I only did a little
> Algol W programming in colledge and that was long ago. I think Cobol also.
On the other hand, before C, both B and BCPL used zero-based indexing.
So if we trace C's family tree, there is certainly precedence for
zero-based indexing into arrays.
https://www.bell-labs.com/usr/dmr/www/kbman.pdf page 8 (PDF page 10)
says:
> 7. A vector is a primary expression followed by any expression in []
> brackets. The two expressions are evaluated to rvalues, added and
> the result is used as an lvalue. The primary expression can be
> thought of as a pointer to the base of a vector, while the bracketed
> expression can be thought of as the offset in the vector. Since
> E1[E2] is identical to *(E1+E2), and addition is commutative, the
> base of the vector and teh offset in the vector can swap positions.
And https://www.bell-labs.com/usr/dmr/www/bcpl.pdf page 11 (PDF page
14) says:
> 4.7 Vector Applications
> /.../
> Semantics: A vector is represented by a pointer to a consecutive
> group of words which are the elements of the vector. The pointer
> points to the zeroth element.
--
Michael Kjörling • https://michael.kjorling.se • michael at kjorling.se
“People who think they know everything really annoy
those of us who know we don’t.” (Bjarne Stroustrup)
next prev parent reply other threads:[~2017-06-07 13:50 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAH_OBiewwwS6kbdWKUO-j3v=Do+Y9AzBn4ZkyVic7LOJN5WX7w@mail.gmail.com>
[not found] ` <CAH_OBid5q-YeB6UYeOfjW68s3nb3TX_icC5dFMapfo=7_q5DUQ@mail.gmail.com>
[not found] ` <CAH_OBideJeNGiiys=VOEYcU1cffSg+6zDOD39HOU74vumQF0kA@mail.gmail.com>
[not found] ` <CAH_OBie_+dQXOC2OaZii5K=j1Ljmv-OvAVXvyypoLJ10jaysWA@mail.gmail.com>
[not found] ` <CAH_OBidXd1Lpgp8ttM3sWLfXDT0ms5EGAzEjPH9QkY+bXyev2w@mail.gmail.com>
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[not found] ` <CAH_OBic3MTy-20C_T2ciT2x+EjNZvXR2PJ0OzB0qRp1gd2OL-g@mail.gmail.com>
2017-06-07 12:56 ` shawn wilson
2017-06-07 13:16 ` Ron Natalie
2017-06-07 13:20 ` arnold
2017-06-07 13:50 ` Michael Kjörling [this message]
2017-06-07 14:02 ` arnold
2017-06-08 11:28 ` Christian Neukirchen
2017-06-08 14:56 ` shawn wilson
2017-06-07 14:58 ` Tony Finch
2017-06-07 23:57 ` Dave Horsfall
2017-06-07 16:31 ` Lyndon Nerenberg
2017-06-08 0:47 ` Bakul Shah
2017-06-07 17:59 ` Tim Bradshaw
2017-06-07 18:29 ` Clem Cole
2017-06-07 18:46 ` Arthur Krewat
2017-06-07 19:03 ` Ron Natalie
2017-06-07 19:15 ` Arthur Krewat
2017-06-07 19:49 ` Ron Natalie
2017-06-08 1:58 ` ARJANEN Loïc Jean David
2017-06-08 13:49 ` Random832
2017-06-08 13:55 ` Arthur Krewat
2017-06-08 18:41 ` Tim Bradshaw
2017-06-08 2:45 ` Robert Swierczek
2017-06-08 4:05 ` Dave Horsfall
2017-06-08 6:19 ` Peter Jeremy
2017-06-08 7:02 ` Dave Horsfall
2017-06-08 13:53 ` Ron Natalie
2017-06-08 2:27 Doug McIlroy
2017-06-08 12:49 ` William Cheswick
2017-06-08 12:56 ` Michael Kjörling
2017-06-08 13:45 ` Dan Cross
2017-06-08 13:57 ` Ron Natalie
2017-06-10 21:08 ` Nemo
2017-06-08 15:04 ` Dave Horsfall
2017-06-08 15:09 ` William Pechter
2017-06-08 16:53 ` Steve Nickolas
2017-06-08 20:17 ` Larry McVoy
2017-06-09 0:03 ` Greg 'groggy' Lehey
2017-06-08 9:16 Richard Tobin
[not found] <mailman.890.1496953026.3779.tuhs@minnie.tuhs.org>
2017-06-08 22:28 ` Johnny Billquist
[not found] <mailman.882.1496854900.3779.tuhs@minnie.tuhs.org>
2017-06-08 18:20 ` David
2017-06-08 18:55 ` Ron Natalie
2017-06-09 21:21 ` Steve Johnson
2017-06-09 21:52 ` Arthur Krewat
2017-06-08 22:29 ` Johnny Billquist
2017-06-08 23:16 ` Ron Natalie
2017-06-08 23:41 ` Steve Nickolas
2017-06-09 15:12 ` Random832
2017-06-09 16:30 ` Ron Natalie
2017-06-09 0:21 ` Johnny Billquist
2017-06-09 0:25 ` Pete Turnbull
2017-06-09 1:19 ` Toby Thain
2017-06-09 2:14 ` Pete Turnbull
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