Re: dynamic_cast

Subject	Re: dynamic_cast
Newsgroups	comp.lang.c++
References	<20210627225136.00005d66@reddwarf.jmc> <sbbr3u$a3j$1@dont-email.me> <sbl7mh$kb5$1@dont-email.me> <sbpm58$tfv$1@dont-email.me>
From	Richard Damon <Richard@Damon-Family.org>
Message-ID	<oMZDI.15364$SA.31@fx39.iad> (permalink)
Organization	Forte - www.forteinc.com
Date	2021-07-03 09:39 -0400

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On 7/3/21 8:45 AM, Bonita Montero wrote:
>> I just did a line count on our codebase; we have about 1 dynamic
>> cast for every 10k lines. Compare with static_cast - 1 in 300.
> 
> Using dynamic_cast instead of a virtual function call is bad coding.

Incorrect, often to add the virtual function call to get around the need
for the dynamic_cast requires injecting into a class concepts that it
should not be dealing with.

As an example, say you have a collection of animals, and you want to
extract all the dogs out of it. You could add to Animal and Dog an isDog
function, (and then need to change Animal again for each new type of
thing you might want get, lousy encapsulation) or you can use a
dynamic_cast to check if this animal is a Dog.

Thread

dynamic_cast Mr Flibble <flibble@reddwarf.jmc> - 2021-06-27 22:51 +0100
  Re: dynamic_cast Öö Tiib <ootiib@hot.ee> - 2021-06-27 15:01 -0700
  Re: dynamic_cast Branimir Maksimovic <branimir.maksimovic@gmail.com> - 2021-06-27 22:30 +0000
  Re: dynamic_cast "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-06-27 16:35 -0700
  Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-06-28 08:44 +0200
    Re: dynamic_cast Vir Campestris <vir.campestris@invalid.invalid> - 2021-07-01 21:14 +0100
      Re: dynamic_cast Öö Tiib <ootiib@hot.ee> - 2021-07-01 14:16 -0700
      Re: dynamic_cast red floyd <no.spam.here@its.invalid> - 2021-07-01 17:48 -0700
      Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-07-03 14:45 +0200
        Re: dynamic_cast Richard Damon <Richard@Damon-Family.org> - 2021-07-03 09:39 -0400
          Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-07-03 15:53 +0200
            Re: dynamic_cast Richard Damon <Richard@Damon-Family.org> - 2021-07-03 09:59 -0400
              Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-07-03 17:01 +0200
                Re: dynamic_cast Richard Damon <Richard@Damon-Family.org> - 2021-07-03 11:42 -0400
                Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-07-03 18:04 +0200
                Re: dynamic_cast Richard Damon <Richard@Damon-Family.org> - 2021-07-03 13:59 -0400
                Re: dynamic_cast Mr Flibble <flibble@reddwarf.jmc> - 2021-07-03 20:06 +0100
                Re: dynamic_cast Bonita Montero <Bonita.Montero@gmail.com> - 2021-07-04 07:06 +0200
                Re: dynamic_cast Richard Damon <Richard@Damon-Family.org> - 2021-07-03 14:03 -0400
                Re: dynamic_cast Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-08-07 13:06 -0700

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