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Groups > comp.lang.c > #100771
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: How is he doing: int a[2] = { 1, 2 }; printf("%d\n", 2[a]); |
| Date | 2017-01-01 13:03 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <87a8bbq6ef.fsf@bsb.me.uk> (permalink) |
| References | (8 earlier) <o465j7$f80$1@dont-email.me> <5868defa.4980093@news.xs4all.nl> <o4apes$n3q$1@dont-email.me> <87ful3q9bt.fsf@bsb.me.uk> <o4arsj$uqe$1@dont-email.me> |
BartC <bc@freeuk.com> writes: > On 01/01/2017 12:00, Ben Bacarisse wrote: >> BartC <bc@freeuk.com> writes: >> >>> On 01/01/2017 10:54, Richard Bos wrote: >>>> BartC <bc@freeuk.com> wrote: >>>> >>>>> On 30/12/2016 16:41, Keith Thompson wrote: >>>> >>>>>> Which exists because there is no unary "-" for pointers, and negating a >>>>>> pointer makes no sense. >>>>> >>>>> Neither does negating an unsigned int. >>>> >>>> There goes someone who has never studied group theory. >>> >>> What does group theory say about 32- and 64-bit pointers? >> >> Nothing as far as I can see. What's your point? There are lots of >> types in C that don't form a group. C's unsigned ints do. > > Where does it say that in the Standard? It doesn't. Not every true statement about C is contained in the standard. > All I can find is something > that says they can never overflow because the values wrap around. From which a set of very useful properties follow. > My original point was that commutative pointer arithmetic is neither > useful nor sensible as it leads to the 2[a] of the subject line. Yes, I know that was your point. As far as I'm concerned that topic is done with -- you think it's neither useful nor sensible and I disagree. I know enough not to try to persuade you otherwise. I was simply correcting a misconception that cropped as as you were trying to justify your position: that negating an unsigned int makes no sense. That's often how these threads go: one thing leads to another. > You can bamboozle me with higher mathematics but that won't stop > people being confused by i[A] when they come across it. I agree. And, for the record, I accept that had C made addition non-commutative where pointers were involved you would not be moaning about it as yet another oddity in the language. By the way, I prefer not to bamboolze people but it's tricky at times because I also don't like to appear patronising by explaining things to people who already know them. In this case I chose not to mention group theory but I did say "additive inverse". My bad. The additive inverse of a value v is simply a value u such that v + u = 0. -- Ben.
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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
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