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Re: Differences between C and C++

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From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c++
Subject Re: Differences between C and C++
Date Mon, 25 Jul 2022 19:38:09 +0100
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Paavo Helde <eesnimi@osa.pri.ee> writes:

> 25.07.2022 18:47 Paavo Helde kirjutas:
>> 25.07.2022 16:14 Juha Nieminen kirjutas:
>>> Some people often object if someone conflates C and C++, as if C++ were
>>> just a pure superset of C, pointing out that they are, in fact, different
>>> languages and, in some aspects, actually incompatible with each other.
>>>
>> #include <stdio.h>
>> #include <stdlib.h>
>> int main() {
>>      double x = -0.5;
>>      int y = (int) 2*abs(x);
>>      printf("%d\n", y);
>> }
>
> This example can be actually made a bit simpler, messing with ints is
> actually not needed. I think this is now similar to what I stomped on
> myself in real code.
>
> #include <stdio.h>
> #include <stdlib.h>
>
> int main() {
>
> 	double x = -0.5;
> 	double y = 2.0 * abs(x);
> 	printf("%g\n", y);
> }

I would have hoped for a warning about that!  gcc gives me one (two, in
fact) if I ask for the kitchen sink:

warning: using integer absolute value function ‘abs’ when argument is of floating-point type ‘double’ [-Wabsolute-value]
    7 |         double y = 2.0 * abs(x);
      |                          ^~~
warning: conversion from ‘double’ to ‘int’ may change value [-Wfloat-conversion]
    7 |         double y = 2.0 * abs(x);
      |                              ^

-- 
Ben.

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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

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