220 19207 <012fd35d-96fd-4775-835e-2105176c4f97@isocpp.org> article Path: news.gmane.org!not-for-mail From: Vlad from Moscow Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Overloading std::begin and std::end for std::pair Date: Thu, 23 Jul 2015 10:36:46 -0700 (PDT) Lines: 100 Approved: news@gmane.org Message-ID: <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_737_309793220.1437673006283" X-Trace: ger.gmane.org 1437673009 8858 80.91.229.3 (23 Jul 2015 17:36:49 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 23 Jul 2015 17:36:49 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCXLLRHD7IDRBL6MYSWQKGQEOUCVBHQ@isocpp.org Thu Jul 23 19:36:49 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ig0-f197.google.com ([209.85.213.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZIKQK-0006Ny-Qz for gclcip-std-proposals@m.gmane.org; Thu, 23 Jul 2015 19:36:49 +0200 Original-Received: by igbij6 with SMTP id ij6sf3267595igb.1 for ; Thu, 23 Jul 2015 10:36:48 -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:message-id: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=5t+uSCz8lFdd7TjoybKuJz7r7TsnmHrzwNbssei5vLA=; b=YTdrr0w9MXtUUBADbtb8Z63d8iBRL5EUnKHaYK/JdycjYIkcTPfefZHssFgrz32Lr9 qP1X7MTILhzArNesEctWG7uSSWlLlp46WAvjXjVTRGTMb5VmExHXeAQT4Eell1SNnzlL pY3jMpc+FxIDIYViRY0vB18vfqPAXWWF6H8Jk3a4obOmA96zrK7ozCseHJ9WMjOezyTg N/yjJPcMEuVOLlKeoUKud01MT9b7IO9PHPAbKsnuHCVBFPsLIK+ugy0TGp7j9xEGsULC 8zIHFDcjpG2RqvyaUo9BKyd3nXXc02P9/laFrUu+sY+/kbQGGSd2o79WXLFaaXPDsDBo YrBw== X-Gm-Message-State: ALoCoQnWRQk0++6ZeY6P0FJ+7WaGRpT73/4BdfZOxt3x/PPQlqp1cV5lytGlsXoROC804VASbK59 X-Received: by 10.182.165.196 with SMTP id za4mr9343569obb.20.1437673007996; Thu, 23 Jul 2015 10:36:47 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.92.246 with SMTP id b109ls1071769qge.83.gmail; Thu, 23 Jul 2015 10:36:46 -0700 (PDT) X-Received: by 10.140.94.166 with SMTP id g35mr204001qge.1.1437673006942; Thu, 23 Jul 2015 10:36:46 -0700 (PDT) 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:19207 Archived-At: ------=_Part_737_309793220.1437673006283 Content-Type: multipart/alternative; boundary="----=_Part_738_963777742.1437673006283" ------=_Part_738_963777742.1437673006283 Content-Type: text/plain; charset=UTF-8 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_738_963777742.1437673006283 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I'd like to =C2=A0suggest very simple and=C2=A0at= the same time very useful=C2=A0 overloaded functions std::begin and std::e= nd for standard class std::pair.

Here is a demonst= rative program of the idea

#include <iostream&g= t;
#include <utility>

namespace st= d
{=C2=A0=C2=A0=C2=A0
template <class Iterator>
Iterator be= gin( 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> &p )
{
= =C2=A0=C2=A0=C2=A0 return p.second;
}
}

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::cout << 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
=C2=A0=C2=A0=C2=A0 for ( auto x : std::ma= ke_pair( b[0] + 1, b[1] + 2 ) ) std::cout << x << ' ';<= br>=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

--

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