220 7182 <2d16db0e-fb46-4e1f-956f-db3407a6fb4c@isocpp.org> article Path: news.gmane.org!not-for-mail From: Vlad from Moscow Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: "count_while" and "count_until" algorithms Date: Tue, 8 Oct 2013 13:56:01 -0700 (PDT) Lines: 136 Approved: news@gmane.org Message-ID: <2d16db0e-fb46-4e1f-956f-db3407a6fb4c@isocpp.org> References: <2602b3fd-fccd-459b-be1a-93a12005dc5c@isocpp.org> <231e6ef1-599d-4877-be6c-55e85e5a4e41@isocpp.org> <6e15fc38-8be3-4e74-ade9-e25a8d0e0509@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_321_28098160.1381265762012" X-Trace: ger.gmane.org 1381265764 14956 80.91.229.3 (8 Oct 2013 20:56:04 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 8 Oct 2013 20:56:04 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXLLRHD7IDRBY7C2GJAKGQEVNT7UMQ@isocpp.org Tue Oct 08 22:56:08 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f200.google.com ([209.85.214.200]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VTeK5-0007O5-8F for gclcip-std-proposals@m.gmane.org; Tue, 08 Oct 2013 22:56:05 +0200 Original-Received: by mail-ob0-f200.google.com with SMTP id wo20sf4548519obc.11 for ; Tue, 08 Oct 2013 13:56:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe :content-type; bh=V5nNehSuSMyVAOmZahTAASDl4lOooXEBmMjzCdNLMWg=; b=AcfDyA+wda1KzqYIGe6jWL07BCQ8LJeEO/wjUQC1i1NlIT9BqRMVBtXRK196N3va2x KZ8/cTGU/Mb3x8HPi7pwSAyMKS4kc5J/iJYE4psnnUEZdUnwW5KWkYMFDpx0dQ+v6rb6 rO4mlNxNGjlMBjHjPtSf9CCFzUxITeVM6Yz/Patqv9R2dO0Zv7VkBXwh4bi0Ix76WGRU Sj2DzZxbHEX0TsGPA4dqjx3FPR6DQ0k3jeFlQolRQZTAJ7Pc2OGPTLhOYmu9Q7Eiy/2d mi6Gvw+Oj10UUZ9NwlyZdwwTBzy8lNTWJe+TVerRXAj+NyiCztcjx1vVYb84v8rcdkk0 QfVQ== X-Received: by 10.50.73.37 with SMTP id i5mr19340795igv.2.1381265764247; Tue, 08 Oct 2013 13:56:04 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.43.232 with SMTP id z8ls3927263igl.32.canary; Tue, 08 Oct 2013 13:56:03 -0700 (PDT) X-Received: by 10.50.23.8 with SMTP id i8mr1072103igf.8.1381265763709; Tue, 08 Oct 2013 13:56:03 -0700 (PDT) In-Reply-To: <6e15fc38-8be3-4e74-ade9-e25a8d0e0509@isocpp.org> 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-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:7182 Archived-At: ------=_Part_321_28098160.1381265762012 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I want to change the name in the context of my proposal of=20 std::accumulate_first_if that there will be a common name for such types of= =20 algorithms. =20 By the way using std::find_if with a predicate resolves the two tasks:=20 returning the count and the last iterator. =20 For example =20 [code] int a[] =3D { 1, 2, 3, 4, 0, 5 }; size_t n =3D 0; std::find_if( std::begin( a ), std::end( a ),=20 [&]( int x ) { return ( !( x =3D=3D 0 ) ? ++n, false : true );= } ); std::cout << n << std::endl; [/code] =20 =D1=81=D1=80=D0=B5=D0=B4=D0=B0, 9 =D0=BE=D0=BA=D1=82=D1=8F=D0=B1=D1=80=D1= =8F 2013 =D0=B3., 0:42:56 UTC+4 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2= =D0=B0=D1=82=D0=B5=D0=BB=D1=8C lefev...@gmail.com=20 =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB: > @Evgeny: Yes, I see the advantage to return both count and iterator, but = I=20 > didn't find an elegant way to do it for the moment. > > @Vlad: Why do you want to change the names? > > > > Le mardi 8 octobre 2013 22:36:57 UTC+2, Evgeny Panasyuk a =C3=A9crit : >> >> 9 oct 2013 =D0=B3., 0:33:18 UTC+4 lefev...@gmail.com : >>> >>> Yes, the behavior is like find_if + distance, but the performance is=20 >>> better (except maybe for random access iterator). I propose a template= =20 >>> specialization for random access iterator in order to be at least as fa= st=20 >>> as find_if + distance. >>> >>> Le mardi 8 octobre 2013 22:27:10 UTC+2, Evgeny Panasyuk a =C3=A9crit : >>>> >>>> I think to make it useful - both count and iterator should be returned= ..=20 >>>> Just think what happens when input range is single pass. >>>> Plus, maybe special versions for RandomAccessIterator via compile time= =20 >>>> dispatch (with better performance) . >>>> >>> >> Just to clarify: do you see that both count and iterator should be=20 >> returned? >> > --=20 ---=20 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 e= mail 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-proposa= ls/. ------=_Part_321_28098160.1381265762012 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I want to change the name in the context of my propos= al of std::accumulate_first_if that there will be a common name for such ty= pes of algorithms.
 
By the way using std::find_if= with a predicate resolves the two tasks: returning the count and the last = iterator.
 
For example
 
[code]
  int a[] =3D { 1, 2, 3, 4, 0, 5 };
 &n= bsp;size_t n =3D 0;
  std::find_if( std::begin( a ), st= d::end( a ),
         &nbs= p;   [&]( int x ) { return ( !( x =3D=3D 0 ) ? ++n, false : t= rue ); } );
  std::cout << n << std::endl;<= br> [/code]
 

=D1=81=D1=80=D0=B5=D0= =B4=D0=B0, 9 =D0=BE=D0=BA=D1=82=D1=8F=D0=B1=D1=80=D1=8F 2013 =D0=B3., = 0:42:56 UTC+4 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2=D0=B0=D1=82=D0=B5= =D0=BB=D1=8C lefev...@gmail.com =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB:=
@Evgeny: Yes, I see the advantage to r= eturn both count and iterator, but I didn't find an elegant way to do it fo= r the moment.

@Vlad: Why do you want to change the names?


Le mardi 8 octobre 2013 22:36:57 UTC+2, Evgeny Panasyuk a =C3=A9crit&n= bsp;:
9 oct 2013 =D0=B3.,= 0:33:18 UTC+4 lefev...@gmail.com :
Yes, the behavior is like find_if + distance, but the performa= nce is better (except maybe for random access iterator). I propose a templa= te specialization for random access iterator in order to be at least as fas= t as find_if + distance.

Le mardi 8 octobre 2013 22:27:10 UTC+2, Evg= eny Panasyuk a =C3=A9crit :
I think to make it useful - both count and iterator should be returned. = Just think what happens when input range is single pass.
Plus, maybe spe= cial versions for RandomAccessIterator via compile time dispatch (with bett= er performance) .

Just to clarify: do you see that both count= and iterator should be returned?

--
 
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