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Re: solution allocation of memory and composite numbers

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On 2014-12-30, Richard Bos <raltbos@xs4all.nl> wrote:
> Geoff <geoff@invalid.invalid> wrote:
>
>> On Fri, 26 Dec 2014 17:13:47 -0800, Keith Thompson <kst-u@mib.org>
>> >ram@zedat.fu-berlin.de (Stefan Ram) writes:
>> >
>> >> if( 1 == scanf( "%d", &i ))
>> >
>> >Personally, I would never advise beginners to write their equality tests
>> >backwards like that.  There's some risk I might have to read their code
>> >some day.
>> 
>> Some shops require it. There's a very good reason for doing it that
>> way, namely the = vs == bug in conditionals.
>
> That bug is a very good reason _not_ to use this hack. Try it when both
> operands are variables... introducing a bug in _some_ of your

Huh? When both operands are variables, the conding convention doesn't apply.
So it provides neither benfit, nor harm.

If either of the variables is const-qualified, then conforming with
the convention means making that one the left operand, in which case
it provides the guard against accidental use of = instead of ==.

> comparisons while at the same time giving yourself a false feeling of
> security is a very good way to create more, not fewer, bugs.

That's more of an argument against having a feeling, not against the practice.

Any tool which promotes safety can give you a feeling of security, such
as, for instance, a type system that is statically checked.

That such things give us some sense of confidence is normal. It is reasonable
to have more confidence when there are more safeguards, if it is in rational
proportion to the power and scope of those safeguards.

> Teach them,
> rather, to pay attention to what they're writing.

What if pride in one's meticulous attention to what you're writing
gives rise to a *feeling* of security? Oops, same problem.

They'll need it
> anyway; this trick only makes not paying attention _more_, not less
> likely.

How so; you have to consciously apply it.  "I find myself
writing an equality comparison.  Which, if any, of the operands is
unmodifiable, that I may make it the left one?"

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solution allocation of memory and composite numbers Dexterr <dejangru@gmail.com> - 2014-12-24 05:52 -0800
  Re: solution allocation of memory and composite numbers Dexterr <dejangru@gmail.com> - 2014-12-24 05:55 -0800
    Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-24 06:41 -0800
      Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-24 20:16 +0000
        Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-24 12:39 -0800
          Re: solution allocation of memory and composite numbers Richard Heathfield <invalid@see.sig.invalid> - 2014-12-24 21:22 +0000
            Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-24 22:33 +0000
              Re: solution allocation of memory and composite numbers Richard Heathfield <invalid@see.sig.invalid> - 2014-12-25 00:54 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-24 18:38 -0800
                Re: solution allocation of memory and composite numbers Vincenzo Mercuri <nomail@yahoo.it> - 2014-12-25 12:07 +0100
                Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-26 22:05 +0000
                Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-26 22:33 +0000
                Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-27 22:08 +0000
                Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-27 23:28 +0000
                Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-29 18:34 +0000
                Re: solution allocation of memory and composite numbers raltbos@xs4all.nl (Richard Bos) - 2014-12-30 19:23 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-26 15:43 -0800
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-26 15:59 -0800
                Re: solution allocation of memory and composite numbers Vincenzo Mercuri <nomail@yahoo.it> - 2014-12-27 14:45 +0100
                Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-27 21:55 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-27 14:07 -0800
                Re: solution allocation of memory and composite numbers Vincenzo Mercuri <nomail@yahoo.it> - 2014-12-27 23:44 +0100
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-27 15:49 -0800
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-27 21:52 -0800
                Re: solution allocation of memory and composite numbers Vincenzo Mercuri <nomail@yahoo.it> - 2014-12-28 15:54 +0100
                Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-28 00:03 +0000
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-26 17:13 -0800
                Re: solution allocation of memory and composite numbers Geoff <geoff@invalid.invalid> - 2014-12-27 10:23 -0800
                Re: solution allocation of memory and composite numbers Stephen Sprunk <stephen@sprunk.org> - 2014-12-27 13:03 -0600
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-27 12:24 -0800
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-27 12:23 -0800
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-27 13:31 -0800
                Re: solution allocation of memory and composite numbers Öö Tiib <ootiib@hot.ee> - 2014-12-27 18:42 -0800
                Re: solution allocation of memory and composite numbers Keith Thompson <kst-u@mib.org> - 2014-12-27 22:07 -0800
                Re: solution allocation of memory and composite numbers raltbos@xs4all.nl (Richard Bos) - 2014-12-30 19:26 +0000
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 20:01 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 12:18 -0800
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 21:15 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 13:49 -0800
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 22:03 +0000
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 23:57 +0000
                Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-30 22:35 +0000
                Re: solution allocation of memory and composite numbers Dr Nick <nospam-4@temporary-address.org.uk> - 2014-12-31 12:24 +0000
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-31 17:08 +0000
                Re: solution allocation of memory and composite numbers Dr Nick <nospam-4@temporary-address.org.uk> - 2014-12-31 17:37 +0000
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 20:09 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 12:24 -0800
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2014-12-30 21:28 +0000
                Re: solution allocation of memory and composite numbers Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-12-30 13:53 -0800
                Re: solution allocation of memory and composite numbers Kaz Kylheku <kaz@kylheku.com> - 2015-01-04 02:22 +0000
                Re: solution allocation of memory and composite numbers Xavier Roche <xroche@free.fr.NOSPAM.invalid> - 2014-12-31 13:32 +0100
                Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-27 01:37 +0000
                Re: solution allocation of memory and composite numbers raltbos@xs4all.nl (Richard Bos) - 2014-12-27 12:19 +0000
                Re: solution allocation of memory and composite numbers gazelle@shell.xmission.com (Kenny McCormack) - 2014-12-27 14:39 +0000
          Re: solution allocation of memory and composite numbers Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-24 22:29 +0000
    Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-24 15:05 +0000
  Re: solution allocation of memory and composite numbers Richard Heathfield <invalid@see.sig.invalid> - 2014-12-24 16:55 +0000
    iso646.h Noob <root@127.0.0.1> - 2014-12-25 18:26 +0100
      Re: iso646.h Geoff <geoff@invalid.invalid> - 2014-12-25 18:31 -0800
        Re: iso646.h Noob <root@127.0.0.1> - 2014-12-26 18:23 +0100
      Re: iso646.h Keith Thompson <kst-u@mib.org> - 2014-12-25 21:31 -0800
        Re: iso646.h fir <profesor.fir@gmail.com> - 2014-12-26 09:42 -0800
  Re: solution allocation of memory and composite numbers Barry Schwarz <schwarzb@dqel.com> - 2014-12-24 09:06 -0800
  Re: solution allocation of memory and composite numbers Richard Heathfield <invalid@see.sig.invalid> - 2014-12-24 16:59 +0000
  Re: solution allocation of memory and composite numbers BartC <bc@freeuk.com> - 2014-12-24 17:26 +0000
    Re: solution allocation of memory and composite numbers asetofsymbols@gmail.com - 2014-12-24 11:42 -0800

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