220 19212 <424cd221-d1c7-4baf-b074-b7f44ee5c82e@isocpp.org> article Path: news.gmane.org!not-for-mail From: Vlad from Moscow Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Overloading std::begin and std::end for std::pair Date: Thu, 23 Jul 2015 12:15:04 -0700 (PDT) Lines: 266 Approved: news@gmane.org Message-ID: <424cd221-d1c7-4baf-b074-b7f44ee5c82e@isocpp.org> References: <012fd35d-96fd-4775-835e-2105176c4f97@isocpp.org> <70492682-c1ac-4d67-9c00-fe8d841aae63@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_804_255530540.1437678905025" X-Trace: ger.gmane.org 1437678910 9881 80.91.229.3 (23 Jul 2015 19:15:10 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 23 Jul 2015 19:15:10 +0000 (UTC) Cc: rs2740@gmail.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCXLLRHD7IDRBO72YSWQKGQEAIMRY6I@isocpp.org Thu Jul 23 21:15:10 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oi0-f72.google.com ([209.85.218.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZILxV-0007PI-Fc for gclcip-std-proposals@m.gmane.org; Thu, 23 Jul 2015 21:15:09 +0200 Original-Received: by oige126 with SMTP id e126sf1677729oig.0 for ; Thu, 23 Jul 2015 12:15:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type:x-original-sender :reply-to:precedence:mailing-list:list-id:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=2cRkrECOmoJcKY5jQ3Gsi/Cu3JK2BZ0jcFWPFhNr5M8=; b=ltIkZxr5u+LFQrtbl05vCfOXecQ1hZM/PXQHu0H8RUdm/KXKyQVwlDkuR/5zl5twk9 uyc0uguBkiLIm0+gfh6UrvhYDbDCA8O3HdE6jQBC8s2itqL6ukioGQv6UljQEYbus8zY ZFkliMx5L+4FaWz82UODMv9zsln4MBZ7UEOF5Vt8bFOvcLtQN7IxtLiko1G0DooxMvOZ DiCp+ged7S0fMB8AAgljeLFGdBs1Ivpuhi48pOhWI/AulXLsUC0tQNSpwHFnaIEUeW+g /5JQgHsr09oC7FSw72rQjac8s0qmgkBCkj+hWDvrwdozDgH+E+Lu7QYxwecSnAo04YvJ jy9w== X-Gm-Message-State: ALoCoQnFyOTGqEo5dLKZQBjD3TKHTUMBTQCuzJvezwM5/rUuGF6yQRAjrqaLM80erMuGwYtFmmhv X-Received: by 10.182.142.72 with SMTP id ru8mr10056690obb.47.1437678908504; Thu, 23 Jul 2015 12:15:08 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.31.194 with SMTP id f60ls1151878qgf.7.gmail; Thu, 23 Jul 2015 12:15:07 -0700 (PDT) X-Received: by 10.140.92.74 with SMTP id a68mr215385qge.14.1437678907374; Thu, 23 Jul 2015 12:15:07 -0700 (PDT) In-Reply-To: X-Original-Sender: vlad.moscow@mail.ru Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:19212 Archived-At: ------=_Part_804_255530540.1437678905025 Content-Type: multipart/alternative; boundary="----=_Part_805_1077728928.1437678905026" ------=_Part_805_1077728928.1437678905026 Content-Type: text/plain; charset=UTF-8 There is nothing said about introducing functions std::begin and std:;end for std::pair. On Thursday, July 23, 2015 at 9:52:23 PM UTC+3, T. C. wrote: > > http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1381 > > > On Thursday, July 23, 2015 at 2:30:02 PM UTC-4, Vlad from Moscow wrote: >> >> And one more example :) >> >> #include >> #include >> #include >> #include >> #include >> >> namespace std >> { >> template >> Iterator begin( const std::pair &p ) >> { >> return p.first; >> } >> template >> Iterator end( const std::pair &p ) >> { >> return p.second; >> } >> } >> int main() >> { >> std::vector v = { 3, 4, 0, 5, 1, 6, 9, 7, 8 }; >> >> for ( auto x : v ) std::cout << x << ' '; >> std::cout << std::endl; >> auto p = std::minmax_element( v.begin(), v.end() ); >> >> if ( std::distance( v.begin(), p.second ) < std::distance( v.begin(), >> p.first ) ) >> { >> std::swap( p.first, p.second ); >> } >> for ( auto x : p ) std::cout << x << ' '; >> std::cout << std::endl; >> } >> >> The program output is >> >> 3 4 0 5 1 6 9 7 8 >> 0 5 1 6 >> >> On Thursday, July 23, 2015 at 8:57:38 PM UTC+3, Vlad from Moscow wrote: >> >>> Another example >>> >>> #include >>> #include >>> #include >>> >>> namespace std >>> { >>> >>> template >>> Iterator begin( const std::pair &p ) >>> { >>> return p.first; >>> } >>> >>> template >>> Iterator end( const std::pair &p ) >>> { >>> return p.second; >>> } >>> >>> } >>> >>> int main() >>> { >>> std::vector v = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; >>> >>> for ( auto x : std::make_pair( v.begin(), v.end() ) ) std::cout << x >>> << ' '; >>> std::cout << std::endl; >>> >>> for ( auto x : std::make_pair( v.rbegin(), v.rend() ) ) std::cout << >>> x << ' '; >>> std::cout << std::endl; >>> } >>> >>> The program output is >>> >>> 0 1 2 3 4 5 6 7 8 9 >>> 9 8 7 6 5 4 3 2 1 0 >>> >>> Enjoy!:) >>> >>> On Thursday, July 23, 2015 at 8:36:46 PM UTC+3, Vlad from Moscow wrote: >>> >>>> I'd like to suggest very simple and at the same time very useful >>>> overloaded functions std::begin and std::end for standard class std::pair. >>>> >>>> Here is a demonstrative program of the idea >>>> >>>> #include >>>> #include >>>> >>>> namespace std >>>> { >>>> template >>>> Iterator begin( const std::pair &p ) >>>> { >>>> return p.first; >>>> } >>>> template >>>> Iterator end( const std::pair &p ) >>>> { >>>> return p.second; >>>> } >>>> } >>>> >>>> int main() >>>> { >>>> int a[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; >>>> >>>> for ( auto x : std::make_pair( a + 3, a + 7 ) ) std::cout << x << ' >>>> '; >>>> std::cout << std::endl; >>>> >>>> int b[][3] = { { 1, 2, 3 }, { 4, 5, 6 } }; >>>> >>>> for ( auto x : std::make_pair( b[0] + 1, b[1] + 2 ) ) std::cout << >>>> x << ' '; >>>> std::cout << std::endl; >>>> } >>>> >>>> The program output is >>>> >>>> 3 4 5 6 >>>> 2 3 4 5 >>>> >>> -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. ------=_Part_805_1077728928.1437678905026 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
There is nothing said about introducing functions std::beg= in and std:;end for std::pair.

On Thursday, July 23, 2015 at 9:52:23= PM UTC+3, T. C. wrote:
<= a onmousedown=3D"this.href=3D'http://www.google.com/url?q\75http%3A%2F%= 2Fwww.open-std.org%2Fjtc1%2Fsc22%2Fwg21%2Fdocs%2Flwg-defects.html%231381\46= sa\75D\46sntz\0751\46usg\75AFQjCNGCnw-GAV0E1QTFZv90wIFhv-vtdQ';return t= rue;" onclick=3D"this.href=3D'http://www.google.com/url?q\75http%3A%2F%= 2Fwww.open-std.org%2Fjtc1%2Fsc22%2Fwg21%2Fdocs%2Flwg-defects.html%231381\46= sa\75D\46sntz\0751\46usg\75AFQjCNGCnw-GAV0E1QTFZv90wIFhv-vtdQ';return t= rue;" href=3D"http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#= 1381" target=3D"_blank" rel=3D"nofollow">http://www.open-std.org/jtc1/sc22/= wg21/docs/lwg-defects.html#1381


On Thursday, July 23, 2015 at 2:30:02 PM UTC-4, Vlad from Moscow wrot= e:
And one more example := )

#include <iostream>
#include <utilit= y>
#include <vector>
#include <algorithm>
#include = <iterator>

namespace std
{=C2=A0=C2=A0=C2= =A0
template <class Iterator>
Iterator begin( const std::pair&= lt;Iterator, Iterator> &p )
{
=C2=A0=C2=A0=C2=A0 return p.firs= t;
}
template <class Iterator>
Iterator end( const st= d::pair<Iterator, Iterator> &p )
{
=C2=A0=C2=A0=C2=A0 retur= n p.second;
}
}
int main()
{
=C2=A0=C2=A0=C2=A0 std::= vector<int> v =3D { 3, 4, 0, 5, 1, 6, 9, 7, 8 };
=C2=A0=C2=A0=C2= =A0
=C2=A0=C2=A0=C2=A0 for ( auto x : v ) std::cout << x <<= ' ';
=C2=A0=C2=A0=C2=A0 std::cout << std::endl;
=C2=A0=C2=A0=C2=A0 auto p =3D std::minmax_element( v.begin(), v.end() );=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 if ( std::distance( v.begin(), = p.second ) < std::distance( v.begin(), p.first ) )
=C2=A0=C2=A0=C2=A0= {
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 std::swap( p.first, p.seco= nd );
=C2=A0=C2=A0=C2=A0 }=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 for ( auto x : p ) std::cout << x <<= ' ';
=C2=A0=C2=A0=C2=A0 std::cout << std::endl;
=
}=C2=A0=C2=A0=C2=A0

The program output is

3 4 0 5 1 6 9 7 8
0 5 1 6

On Thursday, Ju= ly 23, 2015 at 8:57:38 PM UTC+3, Vlad from Moscow wrote:
Another example

<= div>#include <iostream>
#include <utility>
#include <v= ector>

namespace std
{=C2=A0=C2=A0=C2=A0

template <class Iterator>
Iterator begi= n( const std::pair<Iterator, Iterator> &p )
{
=C2=A0=C2=A0= =C2=A0 return p.first;
}

template <class Ite= rator>
Iterator end( const std::pair<Iterator, Iterator> &p= )
{
=C2=A0=C2=A0=C2=A0 return p.second;
}

}

int main()
{
=C2=A0=C2=A0=C2=A0 std:= :vector<int> v =3D { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
=C2=A0=C2=A0= =C2=A0
=C2=A0=C2=A0=C2=A0 for ( auto x : std::make_pair( v.begin(), v.e= nd() ) ) std::cout << x << ' ';
=C2=A0=C2=A0=C2=A0 s= td::cout << std::endl;
=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 f= or ( auto x : std::make_pair( v.rbegin(), v.rend() ) ) std::cout << x= << ' ';
=C2=A0=C2=A0=C2=A0 std::cout << std::endl;<= /div>
}=C2=A0=C2=A0=C2=A0

The program out= put is

0 1 2 3 4 5 6 7 8 9
9 8 7 6 5 4 3 2 1 0=

Enjoy!:)

On Thursday, July 23, 2015 at 8:3= 6:46 PM UTC+3, Vlad from Moscow wrote:
I'd like to =C2=A0suggest very simple and=C2=A0at t= he same time very useful=C2=A0 overloaded functions std::begin and std::end= for standard class std::pair.

Here is a demonstra= tive program of the idea

#include <iostream>=
#include <utility>

namespace std<= br>{=C2=A0=C2=A0=C2=A0
template <class Iterator>
Iterator begi= n( const std::pair<Iterator, Iterator> &p )
{
=C2=A0=C2=A0= =C2=A0 return p.first;
}
template <class Iterator>
It= erator end( const std::pair<Iterator, Iterator> &p )
{
=C2= =A0=C2=A0=C2=A0 return p.second;
}
}

int mai= n()
{
=C2=A0=C2=A0=C2=A0 int a[] =3D { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }= ;
=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 for ( auto x : std::make_pai= r( a + 3, a + 7 ) ) std::cout << x << ' ';
=C2=A0=C2= =A0=C2=A0 std::cout << std::endl;
=C2=A0=C2=A0=C2=A0=C2=A0<= br>=C2=A0=C2=A0=C2=A0 int b[][3] =3D { { 1, 2, 3 }, { 4, 5, 6 } };
=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 for ( auto x : std::make_p= air( b[0] + 1, b[1] + 2 ) ) std::cout << x << ' ';
= =C2=A0=C2=A0=C2=A0 std::cout << std::endl;
}

<= div>The program output is

3 4 5 6
2 3 4 5=C2= =A0=C2=A0=C2=A0

--

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