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Re: Use of const for non-reference parameters

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In article <95tvubFd2pU10@mid.individual.net>,
Ian Collins  <ian-news@hotmail.com> wrote:
>On 06/16/11 08:53 PM, Urs Thuermann wrote:
>> I'm working on a project that uses const for function parameters that
>> are neither references nor pointers, i.e. something like this:
>>
>> 	int foo(const int a) { ... }
>> 	int bar(const string b) { ... }
>>
>> I don't see why this is useful.  Since the argument is copied to the
>> called function it doesn't matter to the caller whether the argument
>> is modified or not.  So why would one want to write code like that?
>
>It doesn't make a lot of sense.  Maybe they forgot the &?
>

It is not needed in the interface definition (albeit not harmful per
se) but in implementation:

int foo(const int a)
{ 
 //... use a without modifying it
}

is comparable to:

int foo()
{
   const int a = getAFromSomewhere();
   // ... use a without modifying it
}

The const, albeit less important than a const& parameter that
documents the interface can still be useful.

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Use of const for non-reference parameters Urs Thuermann <urs@isnogud.escape.de> - 2011-06-16 10:53 +0200
  Re: Use of const for non-reference parameters Ian Collins <ian-news@hotmail.com> - 2011-06-16 21:15 +1200
    Re: Use of const for non-reference parameters yatremblay@bel1lin202.(none) (Yannick Tremblay) - 2011-06-16 11:50 +0000
  Re: Use of const for non-reference parameters "Balog Pal" <pasa@lib.hu> - 2011-06-16 11:35 +0200
    Re: Use of const for non-reference parameters Urs Thuermann <urs@isnogud.escape.de> - 2011-06-16 15:21 +0200
      Re: Use of const for non-reference parameters Marc <marc.glisse@gmail.com> - 2011-06-16 16:25 +0000
  Re: Use of const for non-reference parameters Michael DOUBEZ <michael.doubez@free.fr> - 2011-06-16 02:38 -0700
  Re: Use of const for non-reference parameters Saeed Amrollahi <amrollahi.saeed@gmail.com> - 2011-06-16 03:15 -0700
  Re: Use of const for non-reference parameters "Fred Zwarts \(KVI\)" <F.Zwarts@KVI.nl> - 2011-06-16 13:33 +0200
  Re: Use of const for non-reference parameters Howard Hinnant <howard.hinnant@gmail.com> - 2011-06-16 09:50 -0700
    Re: Use of const for non-reference parameters Michael DOUBEZ <michael.doubez@free.fr> - 2011-06-16 13:22 -0700
      Re: Use of const for non-reference parameters Howard Hinnant <howard.hinnant@gmail.com> - 2011-06-16 13:49 -0700
        Re: Use of const for non-reference parameters Gerhard Fiedler <gelists@gmail.com> - 2011-06-17 11:41 -0300
          Re: Use of const for non-reference parameters "Balog Pal" <pasa@lib.hu> - 2011-06-17 18:40 +0200
            Re: Use of const for non-reference parameters "Thomas J. Gritzan" <phygon_antispam@gmx.de> - 2011-06-17 22:01 +0200
              Re: Use of const for non-reference parameters "Balog Pal" <pasa@lib.hu> - 2011-06-18 03:01 +0200
            Re: Use of const for non-reference parameters Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-17 13:30 -0700
          Re: Use of const for non-reference parameters Howard Hinnant <howard.hinnant@gmail.com> - 2011-06-17 16:51 -0700
  Re: Use of const for non-reference parameters "Johannes Schaub (litb)" <schaub.johannes@googlemail.com> - 2011-06-17 16:35 +0200
  Re: Use of const for non-reference parameters Juha Nieminen <nospam@thanks.invalid> - 2011-06-18 10:14 +0000
    Re: Use of const for non-reference parameters Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-06-18 11:45 +0000
      Re: Use of const for non-reference parameters "Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com> - 2011-06-18 19:27 +0200

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