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Groups > comp.lang.c > #23417

Re: Precedence Misunderstanding

From Willem <willem@toad.stack.nl>
Newsgroups comp.lang.c
Subject Re: Precedence Misunderstanding
Date 2012-07-19 22:02 +0000
Organization Stack Usenet News Service
Message-ID <slrnk0h0vb.r5q.willem@toad.stack.nl> (permalink)
References <ju2p36$qj9$1@dont-email.me> <874np7j8br.fsf@blp.benpfaff.org> <ju4ba5$lso$1@dont-email.me> <slrnk0bjai.1frm.willem@toad.stack.nl> <87d33ry6u0.fsf@bazspaz.fatphil.org>

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Phil Carmody wrote:
) Willem <willem@toad.stack.nl> writes:
)> This is, step by step, what the program will do:
)> 
)> /* Construct for the expression  a && b || c || d && x && y || z */
)> int abcdxyz(int a, int b, int c, int d, int x, int y, int z)
)> {
)>   if (a) {
)>     if (b) {
)>       return 1;
)>     }
)>   }
)>   if (c) {
)>     return 1;
)>   }
)>   if (d) {
)>     if (x) {
)>       if (y) {
)>         return 1;
)>       }
)>     }
)>   }
)>   if (z) {
)>     return 1;
)>   }
)>   return 0;
)> }
)> 
)> Now, as you can see: a, b, c, d, x, y, z are evaluated in that order.
)
) It's possible to evaluate c when you've not evaluated b. There may be
) a weak ordering, but I'm not sure a non-mathematical reading would 
) include that as an interpretation.

Yes, I wrote that piece of code to demonstrate exactly what will
happen, precisely because english wording tends to be so ambiguous.

You can either try to precisify the wording, or you can write in code.

)> Suppose that '&&' had higher precedence, it would become the following:
)
) s/&&/||/

Good catch.  Or s/higher/lower/, of course.


SaSW, Willem
-- 
Disclaimer: I am in no way responsible for any of the statements
            made in the above text. For all I know I might be
            drugged or something..
            No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT

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Thread

Precedence Misunderstanding Charles Richmond <frizzle@aquaporin4.com> - 2012-07-16 23:18 -0500
  Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 21:54 -0700
    Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 22:13 -0700
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-16 22:36 -0700
        Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 13:57 +0100
    Re: Precedence Misunderstanding "Charles Richmond" <numerist@aquaporin4.com> - 2012-07-17 13:35 -0500
      Re: Precedence Misunderstanding "io_x" <a@b.c.invalid> - 2012-07-17 20:48 +0200
      Re: Precedence Misunderstanding Robert Wessel <robertwessel2@yahoo.com> - 2012-07-17 13:45 -0500
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 12:27 -0700
        Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-17 20:20 +0000
      Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:34 +0100
        Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 12:39 -0700
          Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:57 +0100
        Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-17 20:48 +0100
          Re: Precedence Misunderstanding Philip Lantz <prl@canterey.us> - 2012-07-17 21:12 -0700
            Re: Precedence Misunderstanding Ike Naar <ike@iceland.freeshell.org> - 2012-07-18 07:14 +0000
              Re: Precedence Misunderstanding "BartC" <bc@freeuk.com> - 2012-07-18 10:11 +0100
                Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 09:18 -0700
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:10 +0100
                Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-18 18:27 +0100
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:53 +0100
                Re: Precedence Misunderstanding Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-07-18 21:07 +0100
                Re: Precedence Misunderstanding Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-07-19 20:47 +0300
              Re: Precedence Misunderstanding Philip Lantz <prl@canterey.us> - 2012-07-18 23:54 -0700
                Re: Precedence Misunderstanding Ike Naar <ike@sverige.freeshell.org> - 2012-07-19 07:21 +0000
      Re: Precedence Misunderstanding "BartC" <bc@freeuk.com> - 2012-07-17 20:42 +0100
      Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-17 20:38 +0000
        Re: Precedence Misunderstanding Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-07-19 20:54 +0300
          Re: Precedence Misunderstanding Willem <willem@toad.stack.nl> - 2012-07-19 22:02 +0000
      Re: Precedence Misunderstanding pete <pfiland@mindspring.com> - 2012-07-17 22:31 -0400
      Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-18 00:35 -0700
    Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-17 22:16 +0100
      Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-17 14:22 -0700
        Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 16:35 +0100
          Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 10:03 -0700
            Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 18:32 +0100
              Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 10:45 -0700
                Re: Precedence Misunderstanding Rui Maciel <rui.maciel@gmail.com> - 2012-07-18 19:29 +0100
                Re: Precedence Misunderstanding Ben Pfaff <blp@cs.stanford.edu> - 2012-07-18 11:45 -0700
                Re: Precedence Misunderstanding Keith Thompson <kst-u@mib.org> - 2012-07-18 13:26 -0700
                Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-19 00:51 -0700
              Re: Precedence Misunderstanding Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-07-19 00:11 -0700
  Re: Precedence Misunderstanding Robert Wessel <robertwessel2@yahoo.com> - 2012-07-17 00:05 -0500
  Re: Precedence Misunderstanding Ike Naar <ike@iceland.freeshell.org> - 2012-07-17 07:40 +0000

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