Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c++ > #85734

Re: Differences between C and C++

From Muttley@dastardlyhq.com
Newsgroups comp.lang.c++
Subject Re: Differences between C and C++
Date 2022-07-29 09:28 +0000
Organization Aioe.org NNTP Server
Message-ID <tc098n$7sj$1@gioia.aioe.org> (permalink)
References (4 earlier) <jkffqcFbbplU1@mid.individual.net> <tbu8us$t6b$1@gioia.aioe.org> <tbufhe$36veg$1@dont-email.me> <tc03ru$1ld7$1@gioia.aioe.org> <tc07oh$3f6d6$1@dont-email.me>

Show all headers | View raw

On Fri, 29 Jul 2022 12:03:12 +0300
Paavo Helde <eesnimi@osa.pri.ee> wrote:
>29.07.2022 10:56 Juha Nieminen kirjutas:
>> Paavo Helde <eesnimi@osa.pri.ee> wrote:
>>> Why on earth are you using char* in a C++ program? The only thing they
>>> bring is problems and slowdowns (because string length needs to be
>>> re-calculated all the time).
>> 
>> Incorrect. In many situations using char* "strings" is more efficient than
>> using std::string because of the elided dynamic memory allocation. Also,
>> not in all situations is the length of the string needed to be separately
>> calculated in order to operate with the string, as many operations do not
>> need to know the length in advance, and can just stop when they encounter
>> the null byte. (For example printing a char* string doesn't need to know
>> its length in advance. Many other operations likewise.)
>
>Yes, in some situations char* strings can be more efficient. But these 
>situations are pretty rare, and in order to outweigh the drawbacks the 
>performance benefits must be pretty large. Plus, on that level of 
>performance tuning, one needs to really know what one is doing, which Mr 
>Muttley quite clearly does not.

You're in no position to be patronising my friend since you seem to be
unaware of basic char* use cases and how they work.

>First, if I have a std::string literal and pass it to foo(const 
>std::string&), then there is no copies, just a reference is passed. If I 
>have a char* literal, then there is indeed strlen+copy, that's what I 
>was talking about. I think your example actually proves my point.

If you pass a char* there are no copies either. You ever heard of pointers?

>Nowadays std::string is typically using small string optimization, 
>meaning that for sufficiently short strings there is no dynamic 
>allocation either.

Moving the stack pointer to allocate stack memory takes non zero time compared
to using a raw pointer which is already set.

Back to comp.lang.c++ | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-25 13:14 +0000
  Re: Differences between C and C++ "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-07-25 16:18 +0200
  Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-25 18:47 +0300
    Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-25 19:49 +0300
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 19:38 +0100
  Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-25 08:51 -0700
  Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 17:14 +0100
    Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-25 16:19 +0000
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-25 19:28 +0100
      Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-25 12:21 -0700
        Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 07:54 +0000
          Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 08:00 +0000
            Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 08:09 +0000
              Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-26 02:42 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-26 15:29 +0000
                Re: Differences between C and C++ scott@slp53.sl.home (Scott Lurndal) - 2022-07-26 16:30 +0000
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-26 11:59 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-27 07:52 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-27 01:56 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-27 14:51 +0000
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-27 11:11 -0700
    Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 06:09 +0000
      Re: Differences between C and C++ Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-07-27 17:33 +0100
  Re: Differences between C and C++ Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2022-07-25 17:45 +0100
  Re: Differences between C and C++ Paul N <gw7rib@aol.com> - 2022-07-27 10:09 -0700
    Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-07-27 19:28 +0200
      Re: Differences between C and C++ Paul N <gw7rib@aol.com> - 2022-07-27 11:43 -0700
        Re: Differences between C and C++ David Brown <david.brown@hesbynett.no> - 2022-07-29 18:04 +0200
          Re: Differences between C and C++ Richard Damon <Richard@Damon-Family.org> - 2022-07-29 18:47 -0400
            Re: Differences between C and C++ David Brown <david.brown@hesbynett.no> - 2022-07-30 14:08 +0200
      Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 08:03 +0000
        Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-28 01:57 -0700
          Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 09:04 +0000
    Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-28 06:53 +0000
      Re: Differences between C and C++ Richard Damon <Richard@Damon-Family.org> - 2022-07-28 07:33 -0400
        Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-07-28 15:04 +0200
          Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-28 15:11 +0000
            Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-28 20:03 +0300
              Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 07:56 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 12:03 +0300
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 09:28 +0000
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 12:27 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 05:43 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 14:14 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 08:25 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 15:48 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 13:12 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-30 09:28 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 03:39 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-30 14:23 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 19:07 -0700
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-31 07:22 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-31 06:07 -0700
                Re: Differences between C and C++ muttley@dastardlyhq.com - 2022-07-31 16:36 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-08-01 01:12 -0700
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-29 22:47 +0000
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-30 03:48 -0700
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-07-29 05:16 -0700
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-07-30 02:14 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-07-31 14:39 +0000
                Re: Differences between C and C++ "Fred. Zwarts" <F.Zwarts@KVI.nl> - 2022-07-31 18:49 +0200
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-31 14:49 -0700
                Re: Differences between C and C++ Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-31 17:03 -0700
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-01 00:16 -0700
                Re: Differences between C and C++ Ike Naar <ike@sdf.org> - 2022-08-01 07:27 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-01 10:47 +0300
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-01 10:34 +0300
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-08-03 01:20 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-03 07:59 +0000
                Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-08-03 12:45 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-03 10:53 +0000
                Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-08-03 03:58 -0700
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-03 14:49 +0300
                Re: Differences between C and C++ Öö Tiib <ootiib@hot.ee> - 2022-08-03 23:31 -0700
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-01 11:29 +0000
                Re: Differences between C and C++ Bo Persson <bo@bo-persson.se> - 2022-08-01 14:39 +0200
                Re: Differences between C and C++ Juha Nieminen <nospam@thanks.invalid> - 2022-08-02 05:43 +0000
                Re: Differences between C and C++ Manfred <noname@add.invalid> - 2022-08-03 01:13 +0200
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-08-03 09:34 +0300
              Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 09:22 +0000
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 13:53 +0300
                Re: Differences between C and C++ Paavo Helde <eesnimi@osa.pri.ee> - 2022-07-29 14:13 +0300
                Re: Differences between C and C++ Muttley@dastardlyhq.com - 2022-07-29 14:11 +0000
        Re: Differences between C and C++ Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-28 06:16 -0700

csiph-web