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Groups > comp.lang.c++ > #5836

Re: implicit promotion

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On 2011-05-30 02:49:08 -1000, Öö Tiib said:

> On May 30, 2:45 pm, Juha Nieminen <nos...@thanks.invalid> wrote:
>> Paavo Helde <myfirstn...@osa.pri.ee> wrote:
>>>> If you write
>> 
>>>> float tot = (float)sum/tally->size();
>> 
>>>> you then have a float divided by an int, 1.5.
>> 
>>> Yes, for getting floating-point division one needs to cast only one
>>> operand to a floating-point type, the other would be cast to the type of
>>> the first automatically. In the original line from OP both operands were
>>> cast, possibly because the original author liked symmetry or clarity.
>> 
>>   Actually, if a float is divided by an int, aren't both of them cast
>> to double first? (Not that it probably makes any difference in practice,
>> but just pointing out.)
> 
> Most things about floating point arithmetics is implementation defined
> so what really happens depends on platform and compiler.

Not here. Read about "usual arithmetic conversions". If one argument is 
float and the other is int, the int is converted to float.

-- 
  Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The 
Standard C++ Library Extensions: a Tutorial and Reference 
(www.petebecker.com/tr1book)

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implicit promotion Ruben Safir <ruben@mrbrklyn.com> - 2011-05-30 01:44 +0000
  Re: implicit promotion red floyd <no.spam.here@its.invalid> - 2011-05-29 20:35 -0700
    Re: implicit promotion ruben safir <ruben@mrbrklyn.com> - 2011-05-30 00:01 -0400
      Re: implicit promotion Ian Collins <ian-news@hotmail.com> - 2011-05-30 16:08 +1200
        Re: implicit promotion Paavo Helde <myfirstname@osa.pri.ee> - 2011-05-30 01:18 -0500
          Re: implicit promotion Juha Nieminen <nospam@thanks.invalid> - 2011-05-30 11:45 +0000
            Re: implicit promotion Öö Tiib <ootiib@hot.ee> - 2011-05-30 05:49 -0700
              Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 08:58 -1000
                Re: implicit promotion Öö Tiib <ootiib@hot.ee> - 2011-05-30 12:01 -0700
                Re: implicit promotion Öö Tiib <ootiib@hot.ee> - 2011-05-30 12:07 -0700
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 09:07 -1000
                Re: implicit promotion Öö Tiib <ootiib@hot.ee> - 2011-05-30 12:13 -0700
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 09:27 -1000
            Re: implicit promotion Paavo Helde <myfirstname@osa.pri.ee> - 2011-05-30 10:17 -0500
              Re: implicit promotion Juha Nieminen <nospam@thanks.invalid> - 2011-05-30 18:20 +0000
                Re: implicit promotion Paavo Helde <myfirstname@osa.pri.ee> - 2011-05-30 14:06 -0500
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 09:23 -1000
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 09:29 -1000
                Re: implicit promotion Ruben Safir <ruben@mrbrklyn.com> - 2011-05-31 01:24 +0000
                Re: implicit promotion Ian Collins <ian-news@hotmail.com> - 2011-05-31 13:30 +1200
                Re: implicit promotion ruben safir <ruben@mrbrklyn.com> - 2011-05-31 00:52 -0400
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 17:36 -1000
              Re: implicit promotion Öö Tiib <ootiib@hot.ee> - 2011-05-30 11:39 -0700
                Re: implicit promotion Pete Becker <pete@versatilecoding.com> - 2011-05-30 09:02 -1000

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