Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]);

From	Tim Rentsch <txr@alumni.caltech.edu>
Newsgroups	comp.lang.c
Subject	Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]);
Date	2017-01-02 02:40 -0800
Organization	A noiseless patient Spider
Message-ID	<kfnmvf9sq15.fsf@x-alumni2.alumni.caltech.edu> (permalink)
References	<o44tcs$94c$1@dont-email.me> <o44tkb$94c$2@dont-email.me> <62vb6c1hepqggkeueq71hilmd7h5r3sqv0@4ax.com> <5868e00a.5252281@news.xs4all.nl>

Show all headers | View raw

raltbos@xs4all.nl (Richard Bos) writes:

> Barry Schwarz <schwarzb@dqel.com> wrote:
>
>> The expression a[b] is defined to mean *(a+b).  Since a+b evaluates to
>> the same value as b+a, *(a+b) is the same as *(b+a) which can then be
>> expressed a b[a].  Thus the two expressions a[b] is equivalent to
>> b[a].
>>
>> People write 1[a] for the shock value.
>
> I have seen _one_ semi-good use for it:  parallel arrays as an
> alternative to structs.  But that's marginal.

I have run into another case where I thought it actually made
sense.  The pointer variable -- let me call it 'p' -- is being
used as a stack pointer, moving up and down.  If pushes are done
by '*--p = value;', then '0[p]' is the top of the stack, '1[p]'
is one below the top of the stack, and so forth.  Putting the 'p'
inside the brackets corresponds to how the address would be
written in an assembly language if 'p' were an index register.
Seen from that perspective I thought '1[p]' did a better job of
expressing what's going on than 'p[1]' would.

Thread

How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Veek M <vek.m1234@gmail.com> - 2016-12-30 11:35 +0530
  Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Veek M <vek.m1234@gmail.com> - 2016-12-30 11:39 +0530
    Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Barry Schwarz <schwarzb@dqel.com> - 2016-12-29 22:24 -0800
      Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); raltbos@xs4all.nl (Richard Bos) - 2017-01-01 10:56 +0000
        Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-02 02:40 -0800
          Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); raltbos@xs4all.nl (Richard Bos) - 2017-01-03 21:09 +0000
            Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-13 16:30 -0800
  Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2016-12-29 23:35 -0800
  Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); jt@toerring.de (Jens Thoms Toerring) - 2016-12-30 09:59 +0000
    Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 10:43 +0000
      Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-30 12:55 +0000
        Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 13:12 +0000
          Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-30 14:37 +0000
            Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 16:06 +0000
              Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2016-12-30 08:41 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 17:31 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-30 19:20 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 19:41 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2016-12-30 12:46 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-12-31 00:31 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2016-12-30 11:50 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); raltbos@xs4all.nl (Richard Bos) - 2017-01-01 10:54 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 11:35 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 12:00 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 12:16 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 13:03 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 14:52 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 15:42 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 16:14 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 17:18 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2017-01-01 13:09 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-01 19:24 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); bart4858@gmail.com - 2017-01-01 11:24 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 20:05 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2017-01-01 13:11 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 22:25 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 02:00 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-01 13:51 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 21:59 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-01 14:34 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 02:09 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-02 05:44 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 15:18 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-02 15:21 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 17:07 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-02 09:53 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 23:37 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-02 15:07 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ian Collins <ian-news@hotmail.com> - 2017-01-03 12:11 +1300
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-02 15:46 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 00:54 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-03 00:33 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-03 11:11 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-03 11:32 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-03 14:05 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-03 14:23 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 16:04 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-03 16:09 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 17:23 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-03 09:00 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 20:33 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); luser droog <luser.droog@gmail.com> - 2017-01-03 11:40 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-03 12:23 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); luser droog <luser.droog@gmail.com> - 2017-01-03 12:39 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-03 13:51 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-15 22:58 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-16 10:24 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-31 08:36 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-14 00:53 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ian Collins <ian-news@hotmail.com> - 2017-01-03 13:13 +1300
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2017-01-02 15:51 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 00:51 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); jt@toerring.de (Jens Thoms Toerring) - 2017-01-02 23:32 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-02 23:46 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 01:00 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-03 00:42 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ian Collins <ian-news@hotmail.com> - 2017-01-03 21:47 +1300
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-03 01:31 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-03 10:34 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-03 11:19 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-03 16:19 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Thompson <dave.thompson2@verizon.net> - 2017-01-18 07:51 -0500
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Gareth Owen <gwowen@gmail.com> - 2017-01-18 21:30 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Richard Heathfield <rjh@cpax.org.uk> - 2017-01-18 21:45 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); raltbos@xs4all.nl (Richard Bos) - 2017-01-18 21:55 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Gareth Owen <gwowen@gmail.com> - 2017-01-19 22:25 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-02 00:08 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-02 02:05 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-01 09:45 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 19:20 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-01 15:26 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2017-01-01 23:48 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-02 00:25 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2017-01-01 16:44 +0100
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Philip Lantz <prl@canterey.us> - 2017-01-01 23:54 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Keith Thompson <kst-u@mib.org> - 2017-01-01 13:25 -0800
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-01 22:36 +0000
                Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2017-01-01 15:38 -0800
        Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); BartC <bc@freeuk.com> - 2016-12-30 13:42 +0000
          Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); David Brown <david.brown@hesbynett.no> - 2016-12-30 15:07 +0100
    Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); supercat@casperkitty.com - 2016-12-30 10:21 -0800
  Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); Veek M <vek.m1234@gmail.com> - 2016-12-31 07:37 +0530

csiph-web