From 506528363847233654 X-Google-Thread: f78e5,ac8f7c796c0ee2eb X-Google-Attributes: gidf78e5,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!newsfeed-00.mathworks.com!kanaga.switch.ch!switch.ch!news-fra1.dfn.de!newsfeed.velia.net!newsfeed.vmunix.org!peer-uk.news.demon.net!kibo.news.demon.net!news.demon.co.uk!demon!stump.algebra.com!devnull From: jcoffin@taeus.com (Jerry Coffin) Newsgroups: comp.std.c++ Subject: Re: std::pair istream >> operator Date: Mon, 19 Nov 2007 18:18:33 GMT Organization: TAEUS Lines: 35 Sender: mail2news@demon.net Approved: fjh@cs.mu.oz.au (Fergus Henderson , moderator of comp.std.c++) Message-ID: References: <92a741eb-f9f2-40dc-b252-5f53a451af13@w34g2000hsg.googlegroups.com> <84eb137f-aa46-443e-8f6a-912487da73ad@p69g2000hsa.googlegroups.com> NNTP-Posting-Host: news.news.demon.net Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit X-Trace: news.demon.co.uk 1195496335 17068 158.152.254.254 (19 Nov 2007 18:18:55 GMT) X-Complaints-To: abuse@demon.net NNTP-Posting-Date: Mon, 19 Nov 2007 18:18:55 +0000 (UTC) X-Original-To: std-c++@mailman.ucar.edu X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-User-Agent: MicroPlanet-Gravity/2.70.2067 X-Virus-Scanned: amavisd-new at csse.unimelb.edu.au X-Path: comp-std-cpp-robomod!not-for-mail X-Received: (from fjh@localhost) by mulga.csse.unimelb.edu.au (8.13.8+Sun/8.13.8/Submit) id lAJIIX9a015751; Tue, 20 Nov 2007 05:18:33 +1100 (EST) X-Delivered-To: std-c++@mailman.ucar.edu X-Authentication-Warning: mulga.csse.unimelb.edu.au: fjh set sender to devnull@stump.algebra.com using -f X-SMTP-Auth: no X-Newsgroups: comp.std.c++ Xref: g2news1.google.com comp.std.c++:9648 In article <84eb137f-aa46-443e-8f6a- 912487da73ad@p69g2000hsa.googlegroups.com>, andrey_ryabov@bk.ru says... [ ... ] > template > istream & operator >> (istream & in, pair & p) { > return in>>p.first>>p.second; > } > > In my opinion this is the only possible implementation as it is for > operators '<' and '=='. IMO, this is wrong. The members of a pair are frequently delimited by something other than white space, in which case that delimiter has to be taken into account. For example, if you write a map out to a stream, you frequently use something like a colon to separate the items, in which case you have to ignore that colon when you read the data back in. You can/could accomplish that with a ctype facet that treats your chosen delimiter as white space, but that's a rather heavyweight solution, especially if only part of what you're reading from the stream is pairs. -- Later, Jerry. The universe is a figment of its own imagination. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]