220 19209 <70492682-c1ac-4d67-9c00-fe8d841aae63@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 11:30:02 -0700 (PDT) Lines: 237 Approved: news@gmane.org Message-ID: <70492682-c1ac-4d67-9c00-fe8d841aae63@isocpp.org> References: <012fd35d-96fd-4775-835e-2105176c4f97@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_456_1822935554.1437676202900" X-Trace: ger.gmane.org 1437676210 30395 80.91.229.3 (23 Jul 2015 18:30:10 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 23 Jul 2015 18:30:10 +0000 (UTC) Cc: vlad.moscow@mail.ru To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCXLLRHD7IDRBK7FYSWQKGQEO6A6OKQ@isocpp.org Thu Jul 23 20:30:09 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-qk0-f197.google.com ([209.85.220.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZILFt-0000jG-KF for gclcip-std-proposals@m.gmane.org; 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Thu, 23 Jul 2015 11:30:04 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.42.104 with SMTP id b95ls1094970qga.64.gmail; Thu, 23 Jul 2015 11:30:03 -0700 (PDT) X-Received: by 10.140.39.165 with SMTP id v34mr216057qgv.25.1437676203435; Thu, 23 Jul 2015 11:30:03 -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:19209 Archived-At: ------=_Part_456_1822935554.1437676202900 Content-Type: multipart/alternative; boundary="----=_Part_457_782634225.1437676202900" ------=_Part_457_782634225.1437676202900 Content-Type: text/plain; charset=UTF-8 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_457_782634225.1437676202900 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
And one more example :)

#inc= lude <iostream>
#include <utility>
#include <vector>= ;
#include <algorithm>
#include <iterator>

=
namespace std
{=C2=A0=C2=A0=C2=A0
template <class Iter= ator>
Iterator begin( const std::pair<Iterator, Iterator> &= p )
{
=C2=A0=C2=A0=C2=A0 return p.first;
}
template <= class Iterator>
Iterator end( const std::pair<Iterator, Iterator&g= t; &p )
{
=C2=A0=C2=A0=C2=A0 return 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 s= td::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.second );
=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 fo= r ( 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, July 23, 2015 at 8:57:38 PM UTC= +3, Vlad from Moscow wrote:
Another example

#include <iostream>=
#include <utility>
#include <vector>

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

te= mplate <class Iterator>
Iterator begin( const std::pair<Iterato= r, Iterator> &p )
{
=C2=A0=C2=A0=C2=A0 return p.first;
}

template <class Iterator>
Iterator end( con= st 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 f= or ( auto x : std::make_pair( v.begin(), v.end() ) ) std::cout << x &= lt;< ' ';
=C2=A0=C2=A0=C2=A0 std::cout << std::endl;=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 for ( auto x : std::make_pair( v= ..rbegin(), v.rend() ) ) std::cout << x << ' ';
=C2= =A0=C2=A0=C2=A0 std::cout << std::endl;
}=C2=A0=C2=A0=C2=A0=

The program output is

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

Enj= oy!:)

On Thursday, July 23, 2015 at 8:36:46 PM UTC+3, Vlad from Mosc= ow wrote:
I'd l= ike to =C2=A0suggest very simple and=C2=A0at the same time very useful=C2= =A0 overloaded functions std::begin and std::end for standard class std::pa= ir.

Here is a demonstrative program of the idea

#include <iostream>
#include <uti= lity>

namespace std
{=C2=A0=C2=A0=C2=A0
= template <class Iterator>
Iterator begin( const std::pair<Itera= tor, Iterator> &p )
{
=C2=A0=C2=A0=C2=A0 return p.first;
}<= /div>
template <class Iterator>
Iterator end( const std::pair&= lt;Iterator, Iterator> &p )
{
=C2=A0=C2=A0=C2=A0 return p.seco= nd;
}
}

int main()
{
=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_pair( a + 3, a + 7 ) ) std::co= ut << x << ' ';
=C2=A0=C2=A0=C2=A0 std::cout <<= ; std::endl;
=C2=A0=C2=A0=C2=A0=C2=A0
=C2=A0=C2=A0=C2=A0 int b= [][3] =3D { { 1, 2, 3 }, { 4, 5, 6 } };
=C2=A0=C2=A0=C2=A0=C2=A0<= br>=C2=A0=C2=A0=C2=A0 for ( auto x : std::make_pair( b[0] + 1, b[1] + 2 ) )= std::cout << x << ' ';
=C2=A0=C2=A0=C2=A0 std::cout= << std::endl;
}

The program output is

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

--

---
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/<= /a>.
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