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Groups > comp.lang.c > #29459

Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2)

Message-ID <50D049E0.78C5@mindspring.com> (permalink)
Date 2012-12-18 05:48 -0500
From pete <pfiland@mindspring.com>
Organization PF
Newsgroups comp.lang.c
Subject Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2)
References (2 earlier) <874njkjskj.fsf@bazspaz.fatphil.org> <50CFB97C.3988@mindspring.com> <0.3d0bd95e6186d1006003.20121218013242GMT.87a9tcb0w5.fsf@bsb.me.uk> <50CFCC9D.2D2A@mindspring.com> <0.d3d5ff8b39c0ee47e50b.20121218022900GMT.874njkayab.fsf@bsb.me.uk>

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Ben Bacarisse wrote:
> 
> pete <pfiland@mindspring.com> writes:
> 
> > Ben Bacarisse wrote:
> >>
> >> pete <pfiland@mindspring.com> writes:
> >>
> >> > Phil Carmody wrote:
> >> >> Phil Carmody <thefatphil_demunged@yahoo.co.uk> writes:
> >> >> > This reinforces something that I've spotted historically
> >> >> > - there seems to be some strange fetish
> >> >> > for using the swiss-army for(;;)
> >> >> > where while() is perfectly suitable.
> >> >>
> >> >> Perhaps I should have worded those as just
> >> >> "for" and "while", I wasn't
> >> >> trying to imply the "(;;)" part, just the iteration statements.
> >> >
> >> > for (;;) is special.
> >> >
> >> > while () , doesn't compile,
> >> > even though K&R 3.5 says that they are equivalent.
> >>
> >> That's a very odd reading of the text!  I've tried a few times and I
> >> can't get that meaning from what's written in my K&R.
> >
> > The for statement
> >
> >     for (expr1; expr2; expr3)
> >         statement
> >
> > is equivalent to
> >
> >     expr1;
> >     while (expr2) {
> >         statement
> >         expr3;
> >     }
> >
> > except for the behavior of continue, which is described in 3.7.
> 
> Does it not go on to explain what happens when any/all of expr[123] are
> missing?  Mine does.
> 
> Even if you stopped there and chose to ignore the sentences that follow,
> I don't see how you can conclude that the equivalence applies to "for
> (;;)".  You'd have to be sure that expr[123] can be "empty" and that's
> not at all clear.  We've been told about expressions in chapter 2, but
> none of the have been "empty".  We are told, right away, that it's
> possible to omit these parts of the for loop, but the special meaning is
> explained then and there in the sentences that explain that they can be
> omitted.

If 3.5 had said that Superman and his sister
were equivalent except that Superman was a male, as described in 3.7.
and then the text said that Superman had x-ray vision,
I would take that to mean that Supergirl had x-ray vision too.

-- 
pete

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comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Test <test@.nil.invalid.com> - 2012-12-15 15:47 +0200
  Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-15 14:05 +0000
    Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-15 20:26 +0000
      Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-15 20:47 +0000
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Les Cargill <lcargill99@comcast.com> - 2012-12-15 15:34 -0600
          Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-12-16 03:23 -0800
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-15 16:37 -0500
          Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-15 22:10 +0000
            Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-15 17:32 -0500
              Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-15 15:43 -0800
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-16 02:15 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-16 14:21 -0800
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-16 18:34 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 01:15 -0800
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-17 10:30 -0800
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-17 16:07 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-17 08:13 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-17 10:33 -0800
              Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-16 01:24 +0000
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-16 02:19 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-16 13:11 +0000
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Shao Miller <sha0.miller@gmail.com> - 2012-12-16 14:51 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-16 21:16 +0000
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 00:55 -0800
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-17 15:08 +0000
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-20 10:40 -0800
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-15 22:09 +0000
  Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-12-15 06:11 -0800
    Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Les Cargill <lcargill99@comcast.com> - 2012-12-15 13:26 -0600
  Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) James Kuyper <jameskuyper@verizon.net> - 2012-12-15 09:24 -0500
    Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-15 12:21 -0800
      Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) James Kuyper <jameskuyper@verizon.net> - 2012-12-15 16:42 -0500
      Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Philip Lantz <prl@canterey.us> - 2012-12-16 00:09 -0800
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) James Kuyper <jameskuyper@verizon.net> - 2012-12-16 08:46 -0500
          Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-16 14:29 -0800
  Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-16 10:30 -0500
  Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 12:42 +0200
    Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-17 23:07 +0200
      Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-17 19:31 -0500
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-18 01:32 +0000
          Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-17 20:53 -0500
            Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-18 02:29 +0000
              Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-18 05:48 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-12-18 11:26 +0000
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-20 16:20 -0500
                Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Keith Thompson <kst-u@mib.org> - 2012-12-18 03:44 -0800
            Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) James Kuyper <jameskuyper@verizon.net> - 2012-12-17 22:13 -0500
              Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-18 05:40 -0500
        Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-12-20 15:14 +0200
          Re: comma in a c statement, ie for(i=0,i2=0;i<10;i++,i2) pete <pfiland@mindspring.com> - 2012-12-20 16:31 -0500

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