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Groups > comp.lang.misc > #1013

Re: Learning to code by reading code

From "Rod Pemberton" <do_not_have@noavailemail.cmm>
Newsgroups comp.lang.misc, comp.lang.c++
Subject Re: Learning to code by reading code
Date 2012-02-22 06:12 -0500
Organization Aioe.org NNTP Server
Message-ID <ji2ijj$bal$1@speranza.aioe.org> (permalink)
References (11 earlier) <2bc2a617-e283-44c7-9fd3-63d2887b896e@y10g2000vbn.googlegroups.com> <jhuhvb$6sr$1@speranza.aioe.org> <4f42daff$0$14714$5fc3050@news.tiscali.nl> <jhvojb$vch$1@speranza.aioe.org> <54f1f977-d567-4001-b9b8-fa954b93e7a2@s7g2000vby.googlegroups.com>

Cross-posted to 2 groups.

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"Nick Keighley" <nick_keighley_nospam@hotmail.com> wrote in message
news:54f1f977-d567-4001-b9b8-fa954b93e7a2@s7g2000vby.googlegroups.com...
> On Feb 21, 9:35 am, "Rod Pemberton" <do_not_h...@noavailemail.cmm>
> wrote:
> > "Dombo" <do...@disposable.invalid> wrote in message

<snip>

> > > In the past twenty years I have run into maybe 3 or 4
> > > compiler bugs, and about the same number in the libraries
> > > that came with them (on mainstream compilers, the
> > > statistics are a lot worse for some oddball compilers).
>
> > Again, you've confirm my experiences in contrast to NK's claims.
>
> 3 or 4 in 20 years sounds about right to me (a little high). Sounds
> pretty low to me.

The problem is they are a source of error you haven't located, but should.

> NK claimed bugs in compilers were pretty unusual.
> Sounds like we agree.

Yes, I'd agree that you can agree with yourself and reference yourself in
the third person too ...

> > > Even if you analyze the assembly output, you still don't know
> > > if the code executes as intended.
>
> > Exactly. You won't know the code executes as intended
> > until it is executed,
>
> you can have a pretty good idea.

Since when is "a pretty good idea" equivalent to confirming correctness of
execution?

> And saring at megabytes of assembler
> ain't gonna help you.

Do you stare at megabytes of HLL code too?  That won't help you either ...

> > which was why I asked this of NK:
>
> > RP> How do you confirm correctness of both high-level and
> > RP> low-level code with an imaginary machine? Is your
> > RP> confirmation of correctness imaginary also? ...
>
> oh were you asking if I did unit tests? Yes various validations are
> done ***on the HLL code***. Including inspection, unit test and
> system test. Whats that got to do with asesmbly code?

Is the code executed as part of these tests?  I.e., confirmed, but not
confirmed on an "imaginary machine" ...

(PS.  Are you aware two letters in your various words have their locations
switched?  It's been quite a few times now ... asesmbly vs. assembly
... -ign vs. -ing ... etc)

> > To which, I got more than one absurd response that
> > imaginary confirmation of correctness was entirely valid ...
>
> have you heard of DbC or code inspection?

By DbC, you mean like MISRA C, Safer C, or static code analysis, dynamic
code analysis ... or something else?

Wikipedia's DbC page mentions preconditions.  I'd say that was the over 500
identical cut-n-pasted if() statements to determine if our data was in the
correct location of the 5Mloc program I once worked on ...  No we couldn't
procedurize that if().  That would've been too slow, supposedly.

Wait ... what?!?!  So, you believe in code inspection of the HLL code, but
*not* the emitted assembly?  Well, I just don't know what to say about that
contradiction ...  Are you playing Devil's advocate?


Rod Pemberton

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Re: Learning to code by reading code (was: The way to read STL source code) "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-18 19:00 -0500
  Re: Learning to code by reading code "MikeWhy" <boat042-nospam@yahoo.com> - 2012-02-18 22:34 -0600
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
    Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-19 10:42 +0100
      Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-19 22:34 +0000
        Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-20 12:22 +0100
    Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 03:39 -0500
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
    Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-19 08:40 -0800
      Re: Learning to code by reading code "MikeWhy" <boat042-nospam@yahoo.com> - 2012-02-19 13:17 -0600
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 02:32 -0800
          Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 13:02 +0100
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:09 -0800
              Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 15:11 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 07:39 -0800
      Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 04:14 -0500
        Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-20 11:14 +0100
          Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:13 -0800
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 02:49 -0800
          Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-20 13:02 +0100
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-20 05:18 -0800
              Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-20 13:53 +0000
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 01:32 -0800
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-21 16:16 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 08:40 -0800
          Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-20 17:36 -0500
            Re: Learning to code by reading code Dombo <dombo@disposable.invalid> - 2012-02-21 00:45 +0100
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:35 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 08:48 -0800
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 00:12 -0800
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 06:12 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 04:30 -0800
                Re: Learning to code by reading code Geoff <geoff@invalid.invalid> - 2012-02-22 10:45 -0800
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-23 01:12 -0800
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 07:34 -0500
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-23 05:46 -0800
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 08:38 +0100
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 08:40 +0100
                Re: Learning to code by reading code "io_x" <a@b.c.invalid> - 2012-02-24 09:38 +0100
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-25 05:25 -0500
                Re: Learning to code by reading code Dombo <dombo@disposable.invalid> - 2012-02-25 12:50 +0100
                Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-25 06:13 -0800
                Re: Learning to code by reading code Gareth Owen <gwowen@gmail.com> - 2012-02-26 07:20 +0000
            Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 08:23 +0000
              Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 08:43 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:47 -0500
                Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 10:09 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:38 -0500
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-21 04:31 -0500
                Re: Learning to code by reading code Juha Nieminen <nospam@thanks.invalid> - 2012-02-21 10:05 +0000
                Re: Learning to code by reading code "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2012-02-21 12:21 +0100
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 06:04 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-21 11:01 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:59 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-22 12:59 +0000
                Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 07:03 -0500
                Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-24 14:20 +0000
            Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-21 01:27 -0800
        Re: Learning to code by reading code Peter Remmers <p.remmers@expires-2011-04-30.arcornews.de> - 2012-02-20 22:25 +0100
          Re: Learning to code by reading code Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-26 08:47 +0000
            Re: Learning to code by reading code "BartC" <bc@freeuk.com> - 2012-02-26 10:55 +0000
        Re: Learning to code by reading code Nomen Nescio <nobody@dizum.com> - 2012-02-22 08:59 +0100
          Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-22 05:59 -0500
            Re: Learning to code by reading code Nomen Nescio <nobody@dizum.com> - 2012-02-22 13:47 +0100
              Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-23 06:21 -0500
        Re: Learning to code by reading code Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-22 00:08 -0800
  Re: Learning to code by reading code "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2012-02-19 03:54 -0500
  Re: Learning to code by reading code Marco van de Voort <marcov@toad.stack.nl> - 2012-02-19 11:27 +0000

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