220 7164 article Path: news.gmane.org!not-for-mail From: Philipp Stephani Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: "count_while" and "count_until" algorithms Date: Tue, 8 Oct 2013 22:28:39 +0200 Lines: 304 Approved: news@gmane.org Message-ID: References: <3c5637a3-5760-4825-83e1-c4bfc062e652@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a11c37a0832378904e8409dfa X-Trace: ger.gmane.org 1381264117 28300 80.91.229.3 (8 Oct 2013 20:28:37 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 8 Oct 2013 20:28:37 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBD35NAXJW4GBB6GV2GJAKGQE6W25IHI@isocpp.org Tue Oct 08 22:28:41 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ea0-f198.google.com ([209.85.215.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VTdtZ-0000fn-Fu for gclcip-std-proposals@m.gmane.org; Tue, 08 Oct 2013 22:28:41 +0200 Original-Received: by mail-ea0-f198.google.com with SMTP id z15sf11890090ead.1 for ; Tue, 08 Oct 2013 13:28:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=AU5WvbJ/lLo05PWrnTR4vB4bdqIEpLS+AHdiXSwYciY=; b=jmhGbDcoKWfXS5ODpdeHI7ohWsWT1jPgouIFcKNSeuYJUrX013kou7voYMAjKzStZ0 tMEhvEtnsMiinfi8+S32dY/kVum2sD0AjUb5VLmgoRTJP4/Im44ItiJtlPUoH6x3juLx uCUU9ryntODl8mq/dnu9BdBIEniIpKR8t7OG4EHAkjTUfWpJeTjaMuhGzdIBd4v4UCKv IhRrdv3CkEw3XIC2MbfVdCZUA3uOlcb+28OtcyZkeHMSZklhqipf3uWP0R4Ce7gH/Tu/ tgU+187JdWhjOO3+RGlJL5Sza6MUJe04dbyG19XiCgD7V1qceh8b0rI8nuIzBzEdtgA6 087A== X-Received: by 10.180.36.97 with SMTP id p1mr1400517wij.3.1381264120847; Tue, 08 Oct 2013 13:28:40 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.180.106.6 with SMTP id gq6ls225650wib.34.gmail; Tue, 08 Oct 2013 13:28:40 -0700 (PDT) X-Received: by 10.205.15.72 with SMTP id pt8mr3400084bkb.17.1381264120153; Tue, 08 Oct 2013 13:28:40 -0700 (PDT) Original-Received: from mail-la0-x22f.google.com (mail-la0-x22f.google.com [2a00:1450:4010:c03::22f]) by mx.google.com with ESMTPS id ud6si605358bkb.290.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 08 Oct 2013 13:28:40 -0700 (PDT) Received-SPF: pass (google.com: domain of p.stephani2@gmail.com designates 2a00:1450:4010:c03::22f as permitted sender) client-ip=2a00:1450:4010:c03::22f; Original-Received: by mail-la0-f47.google.com with SMTP id eo20so7296525lab.20 for ; Tue, 08 Oct 2013 13:28:39 -0700 (PDT) X-Received: by 10.112.14.3 with SMTP id l3mr3904269lbc.27.1381264119705; Tue, 08 Oct 2013 13:28:39 -0700 (PDT) Original-Received: by 10.112.213.73 with HTTP; Tue, 8 Oct 2013 13:28:39 -0700 (PDT) In-Reply-To: <3c5637a3-5760-4825-83e1-c4bfc062e652@isocpp.org> X-Original-Sender: p.stephani2@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of p.stephani2@gmail.com designates 2a00:1450:4010:c03::22f as permitted sender) smtp.mail=p.stephani2@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com 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:7164 Archived-At: --001a11c37a0832378904e8409dfa Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable That doesn't work if you can make only a single pass through the range. 2013/10/8 Vlad from Moscow > Till now I do not see any great sense in introducing these algorithms. Th= e > first algorithm is in fact equivalent to > > std::distance( first, std::find_if( first, last, std::not_equal_to() ) > ); > > The second algorithm is equivalent to > > std::distance( first, std::find_if( first, last, std::equal_to() ) ); > > > =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., 0:04:23 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 R=C3=A9my Lefevre =D0=BD=D0=B0=D0=BF=D0=B8= =D1=81=D0=B0=D0=BB: > >> Hi, >> >> I thought about two new algorithms, that could be named "count_while" an= d >> "count_until". Here are their behavior: >> >> template >> >> >> typename iterator_traits**::difference_type >> >> >> count_while (InputIterator first, InputIterator last, UnaryPredicate= pred) >> >> { >> typename iterator_traits**::difference_type ret =3D 0; >> >> >> while (first!=3Dlast && pred(*first)) { >> >> >> ++ret; >> ++first; >> >> >> } >> return ret; >> >> } >> >> >> template >> >> >> typename iterator_traits**::difference_type >> >> >> count_until (InputIterator first, InputIterator last, UnaryPredicate= pred) >> >> { >> >> typename iterator_traits**::difference_type ret =3D 0; >> >> >> while (first!=3Dlast && !pred(*first)) { >> >> >> ++ret; >> ++first; >> >> >> } >> return ret; >> >> >> } >> >> >> What do you think about adding these two components to the algorithms >> library ? >> > -- > > --- > 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/. > --=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/. --001a11c37a0832378904e8409dfa Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
That doesn't work if you can make only a single pass t= hrough the range.


2013/10/8 Vlad from Moscow <vlad.moscow@mail.ru>
Till now=C2=A0I do not= see any great sense in introducing these algorithms. The first algorithm i= s in fact equivalent to
=C2=A0
std::distance( first, std::find_if( first, last, std:= :not_equal_to<T>() ) );
=C2=A0
The second algorit= hm is equivalent to
=C2=A0
std::distance( first, std::f= ind_if( first, last, std::equal_to<T>() ) );
=C2=A0

=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=C2=A0=D0=B3., 0:04:23 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 R=C3=A9my Lefe= vre =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB:
Hi,

I thought about two new algorithms, that could = be named "count_while" and "count_until". Here are thei= r behavior:

template <class InputIterator, class UnaryPredicate&=
gt;



=C2=A0 typename=
 iterator_traits<=
;InputIterator>::difference_type<=
br>


=C2=A0 =C2=A0 count_while (InputIterator fi=
rst, =
InputIterator last, =
UnaryPredicate pred)



{
=C2=A0 =
typename iterator_traits<InputIterator>::difference_type ret =3D 0;



=C2=A0 while (f=
irst!=3Dlast && pred(*first)) {



=C2=A0 =C2=A0 ++ret;
=
=C2=A0 =C2=A0 ++first;


=C2=A0 }
=
=C2=A0 return ret;


}

template <class InputIterator, class UnaryPredicate&=
gt;



=C2=A0 typename=
 iterator_traits<=
;InputIterator>::difference_type<=
br>


=C2=A0 =C2=A0 count_until (InputIterator fi=
rst, =
InputIterator last, =
UnaryPredicate pred)



{
<=
pre>=C2=A0 typename iterator_traits<InputIte=
rator>::difference_type ret =3D 0;



=C2=A0 while (f=
irst!=3Dlast && !pred(*first)) <=
/span>{



=C2=A0 =C2=A0 ++ret;
=
=C2=A0 =C2=A0 ++first;


=C2=A0 }
=
=C2=A0 return ret;


}

What do you think about adding these two components to the algorithms l= ibrary ?

--
=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-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/gro= up/std-proposals/.

--
 
---
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-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/<= /a>.
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