220 7169 <82850309-b16b-44bd-b478-e2e63e43d6ca@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 13:35:01 -0700 (PDT) Lines: 324 Approved: news@gmane.org Message-ID: <82850309-b16b-44bd-b478-e2e63e43d6ca@isocpp.org> References: <285a478e-ce03-42b9-9196-c7d0855e11aa@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_553_17807967.1381264501917" X-Trace: ger.gmane.org 1381264502 32399 80.91.229.3 (8 Oct 2013 20:35:02 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 8 Oct 2013 20:35:02 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXLLRHD7IDRB56Y2GJAKGQEDYT2MXI@isocpp.org Tue Oct 08 22:35:05 2013 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-oa0-f72.google.com ([209.85.219.72]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VTdzl-0004Ig-1p for gclcip-std-proposals@m.gmane.org; Tue, 08 Oct 2013 22:35:05 +0200 Original-Received: by mail-oa0-f72.google.com with SMTP id i4sf1591184oah.7 for ; Tue, 08 Oct 2013 13:35:04 -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=LEd5N1BpEc1Qm77gOJJkp4RsHx8cLDuFCUC/UosrK+0=; b=bTI15uA5HHJfbStS3pyLXUDw75DrrDFT+xQ0qB2jFCZ3jm4b/KvXlJdcjx5M+OITWK Rm48X+AOPNdiyRO7KUO5bpuuQffeClFXTl4++UkJRG818mWvS3B0/KW5UpTGf0JHWIdW Z0PLMpkfiVqcmMAt7YXzI2Qm57NXCcg+1aO6FC9njyK7jH1m2hCtigBsGBw/WLMjLCY3 Kj/dDySXu60dQZ9Z2TLFTuX3wvd9zyyloQgwv7cQYuTJ9FCgLQ/TfsUa8YIUuQHZP0Nr N16RhvUWCP8oYRpHXesA95irWe+PzDA5sf/56ybPRmIMMKjyvNXadFBbCBh96Mn0c1c+ an8Q== X-Received: by 10.50.106.116 with SMTP id gt20mr19279690igb.0.1381264503951; Tue, 08 Oct 2013 13:35:03 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.108.45 with SMTP id hh13ls648127igb.29.gmail; Tue, 08 Oct 2013 13:35:03 -0700 (PDT) X-Received: by 10.50.16.111 with SMTP id f15mr1065028igd.2.1381264503518; Tue, 08 Oct 2013 13:35:03 -0700 (PDT) In-Reply-To: <285a478e-ce03-42b9-9196-c7d0855e11aa@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:7169 Archived-At: ------=_Part_553_17807967.1381264501917 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Or the following definition =20 [code] template T accumulate_first_if( InputIterator first,=20 InputIterator last, T init, UnaryPredicate unary_predicate ) { for ( ; first !=3D last && unary_predicate( *first ) ; ++first ) { init =3D ( T )( init + *first ); } return ( init ); } [/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., 0:32:31 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 Vlad from Moscow=20 =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB: > =20 > [code] > In some thread here I proposed the similar idea for algorithm=20 > std::accumulate. > template BinaryOperation> > T accumulate_first_if( InputIterator first,=20 > InputIterator last, > T init, > UnaryPredicate unary_predicate, > BinaryOperation binary_operation ) > { > for ( ; first !=3D last && unary_predicate( *first ) ; ++first ) > { > init =3D binary_operation( init, *first ); > } > return ( init ); > } > [/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., 0:04:23 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=20 >> "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=20 >> library ? >> > --=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_553_17807967.1381264501917 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Or the following definition
 
[code]
template <class InputIterator, class T, class UnaryPr= edicate>
T accumulate_first_if( InputIterator first,
  =             &nb= sp;     InputIterator last,
    =     T init,
        Un= aryPredicate unary_predicate )
{
 for ( ; first !=3D last &&= amp; unary_predicate( *first ) ; ++first )
 {
  init = =3D ( T )( init + *first );
 }
 return ( init );
= }
[/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., 0:32:31 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 Vl= ad from Moscow =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0=D0=BB:
 
[code]
I= n some thread here I proposed the similar idea for algorithm std::accumulat= e.
template <class InputIterator, class T, class UnaryPredicat= e, class BinaryOperation>
T accumulate_first_if( InputIterator first,=
           &nbs= p;        InputIterator last,
 &= nbsp;      T init,
    &nbs= p;   UnaryPredicate unary_predicate,
    &= nbsp;   BinaryOperation binary_operation )
{
 for ( ; = first !=3D last && unary_predicate( *first ) ; ++first )
 {=
  init =3D binary_operation( init, *first );
 }
=
 return ( init );
}
[/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., 0:04:23 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 tho= ught about two new algorithms, that could be named "count_while" and "count= _until". Here are their behavior:

template<=
/span> <class InputIterator, class UnaryP=
redicate>


  typename iterator_traits<InputIterator>::difference_type


    count_while (=
InputIterator first, InputIterator last, UnaryPredicate pred)


{
  typename iterator_tr=
aits<InputIterator>::diff=
erence_type ret =3D<=
span style=3D"color: rgb(0, 0, 0);"> 0;


  while (first!=3Dlast && pred(*first)) {


    ++ret;
    ++first;


  }
  return ret;


}
= 

template<=
/span> <class InputIterator, class UnaryP=
redicate>


  typename iterator_traits<InputIterator>::difference_type


    count_until (=
InputIterator first, InputIterator last, UnaryPredicate pred)


{
  typename<=
/var> iterator_traits<InputIterator>::difference_type ret =3D 0;


  while (first!=3Dlast && !pred(*first)) {


    ++ret;
    ++first;


  }
  return ret;<=
br>

}

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

--
 
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