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Re: two's complement idea

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c++
Subject Re: two's complement idea
Date 2020-01-27 22:13 +0100
Organization A noiseless patient Spider
Message-ID <r0njph$86d$1@dont-email.me> (permalink)
References (9 earlier) <49pr2fphchn3dk2hiqv2bk8ml5oijs0d6e@4ax.com> <DZmXF.242725$_R5.99089@fx19.am4> <p3ks2f1vekfr0dckvguuvkrdr6lrpedrsl@4ax.com> <VhGXF.46342$BA5.20568@fx21.am4> <e1hu2f5p960nhg1spsvndon031nop7ldhr@4ax.com>

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On 27/01/2020 21:18, Robert Wessel wrote:
> On Mon, 27 Jan 2020 18:50:28 +0000, Bart <bc@freeuk.com> wrote:
> 
>> On 27/01/2020 03:02, Robert Wessel wrote:

<snip>

>>>   The label makes the association with the loop/switch
>>> of interest explicit.  I view the issue as similar to that of
>>> significant white space for flow control (as in Python).  A small
>>> advantage is that a meaningful label can provide documentation.
>>
>> Any label is going to be similar to a goto label (possibly, identical).
>>
>> That makes:
>>
>>      break L;
>>      ...
>>     }
>>   }
>> L:                 // or maybe the label is at the beginning
>>
>> not that different to:
>>
>>     goto L;
>>     ...
>>    }
>>   }
>> L:
>>
>> (Problem using a regular label is that you have to search the code to
>> see if you get there from goto, break, or both.)
> 
> 
> No the labels would be on the loop/switch statement.  So:
> 
>    outerloop: for(...)
>      {
>      for(...)
>        {
>        ...
>        if (...)
>          break outerloop;
>        ...
>        }
>      }
> 
> That has two advantages - the label actually refers to the loop (or
> switch you're trying to do something with), and second, it's a natural
> extension to the language - labels are already (somewhat over
> simplified) a prefix on a statement.  So valid targets for a
> break/continue are just enclosing statements of the right type with a
> label.
> 

That strikes me as a neat and clear way to break out of a nested loop. 
In particular, it avoids the over-flexibility of goto - you can break 
out of a loop, but you can't jump to arbitrary points in the code.  And 
a label makes it clear what you want to exit.

My preference is still mainly to have loop conditionals that cover all 
cases, so breaks (or early returns or other exits) should be rare.  But 
if you need to break out of a nested loop, this would be a good way to 
handle it.

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Thread

Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-28 12:19 -0800
  Re: two's complement idea "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-11-29 00:14 +0100
    Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2019-11-29 09:15 +0100
      Re: two's complement idea Bo Persson <bo@bo-persson.se> - 2019-11-29 10:58 +0100
        Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2019-11-29 12:49 +0100
    Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-12-07 07:53 -0800
      Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2019-12-07 08:22 -0800
        Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-10 20:44 -0800
          Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-10 23:44 -0800
            Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-14 07:08 -0800
              Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-14 08:42 -0800
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-21 02:09 -0800
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-21 05:14 -0800
                Re: two's complement idea Daniel <danielaparker@gmail.com> - 2020-01-21 13:08 -0800
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-22 00:07 -0500
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-21 23:21 -0800
                Re: two's complement idea Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-22 01:51 -0800
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-22 11:28 +0100
                Re: two's complement idea Bonita Montero <Bonita.Montero@gmail.com> - 2020-01-22 11:52 +0100
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-22 04:47 -0800
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 07:19 -0700
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-04-02 08:07 -0700
                Re: two's complement idea boltar@nowhere.org - 2020-01-21 16:44 +0000
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-21 20:01 +0000
                Re: two's complement idea boltar@nowhere.org - 2020-01-22 11:26 +0000
                Re: two's complement idea Christian Gollwitzer <auriocus@gmx.de> - 2020-01-22 20:04 +0100
                Re: two's complement idea Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-22 11:30 -0800
                Re: two's complement idea Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2020-01-22 19:57 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-23 10:03 +1300
                Re: two's complement idea boltar@nowhere.org - 2020-01-23 09:24 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-24 07:29 +1300
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-23 10:03 +1300
                Re: two's complement idea "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2020-01-23 10:09 +0100
                Re: two's complement idea boltar@nowhere.org - 2020-01-23 09:29 +0000
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-24 01:08 +0000
                Re: two's complement idea boltar@nowhere.org - 2020-01-24 12:27 +0000
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-24 01:06 +0000
                Re: two's complement idea Bo Persson <bo@bo-persson.se> - 2020-01-24 10:07 +0100
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-01-24 11:36 +0200
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-24 17:34 -0800
                Re: two's complement idea Siri Cruise <chine.bleu@yahoo.com> - 2020-01-24 17:57 -0800
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-24 12:19 +0000
                Re: two's complement idea Bo Persson <bo@bo-persson.se> - 2020-01-24 14:19 +0100
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-24 14:11 +0000
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-24 17:26 +0000
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-24 17:35 +0000
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-01-24 22:27 +0200
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-24 23:21 -0500
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-25 11:06 +1300
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-24 22:12 +0000
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-24 23:24 -0500
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-25 09:04 +0000
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-25 04:15 -0800
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-25 19:55 +0100
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-25 00:05 +0100
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 01:19 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-25 19:50 +1300
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 11:57 +0000
                Re: two's complement idea Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2020-01-25 13:42 +0000
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 14:58 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-26 07:58 +1300
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-25 20:34 +0100
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-25 12:41 -0800
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-01-26 16:08 +0200
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-27 02:20 -0800
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-01-27 15:03 +0200
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-02-15 06:44 -0800
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-03-06 10:18 +0200
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-02 07:05 -0700
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-04-02 20:03 +0300
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-04-04 12:37 -0700
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-26 07:45 +1300
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 19:56 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-26 09:49 +1300
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 21:33 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-26 11:00 +1300
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-25 22:23 +0000
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-26 11:46 +1300
                Re: two's complement idea Paavo Helde <myfirstname@osa.pri.ee> - 2020-01-26 10:55 +0200
                Re: two's complement idea Öö Tiib <ootiib@hot.ee> - 2020-01-26 03:47 -0800
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-27 01:28 -0800
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-25 22:22 +0000
                Re: two's complement idea James Kuyper <jameskuyper@alumni.caltech.edu> - 2020-01-25 18:24 -0500
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-26 12:54 +0100
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-26 12:44 +0000
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-26 14:58 +0100
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-26 14:53 +0000
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-26 19:10 +0100
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-26 13:20 -0600
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-26 20:51 +0000
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-26 21:02 -0600
                Re: two's complement idea Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-26 19:06 -0800
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-27 18:50 +0000
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-27 14:18 -0600
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-27 22:13 +0100
                Re: two's complement idea Bart <bc@freeuk.com> - 2020-01-27 21:38 +0000
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-27 19:37 -0600
                Re: two's complement idea Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-01-27 19:15 -0800
                Re: two's complement idea "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2020-01-28 11:45 +0100
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-27 16:31 +1300
                Re: two's complement idea Manfred <noname@add.invalid> - 2020-01-26 18:50 +0100
                Re: two's complement idea Jorgen Grahn <grahn+nntp@snipabacken.se> - 2020-01-26 18:57 +0000
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-26 20:46 +0100
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-26 13:14 -0600
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-26 22:15 +0100
                Re: two's complement idea Robert Wessel <robertwessel2@yahoo.com> - 2020-01-27 21:06 -0600
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-28 13:08 +0100
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-27 01:50 -0800
                Re: two's complement idea Ian Collins <ian-news@hotmail.com> - 2020-01-27 08:21 +1300
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-25 20:14 +0100
                Re: two's complement idea David Brown <david.brown@hesbynett.no> - 2020-01-25 20:12 +0100
                Re: two's complement idea Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-01-27 07:48 -0800
                Re: two's complement idea Bonita Montero <Bonita.Montero@gmail.com> - 2020-02-18 18:46 +0100

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