From 1742738864381638850 X-Google-Thread: 7894ca11fe,421cd8b98acf7c5 X-Google-Attributes: gid7894ca11fe,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news2.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 26 Oct 2009 15:30:08 -0500 Return-Path: To: (Usenet) From: =?ISO-8859-1?Q?Daniel_Kr=FCgler?= Newsgroups: comp.std.c++ Subject: Re: Why there are both complex::real and std::real? Organization: http://groups.google.com Sender: cppmods@cs.rpi.edu Approved: austern@google.com Message-ID: References: <210ca399-bea2-47bf-b614-f4cef8fe25fd@k26g2000vbp.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1 X-Original-Date: Mon, 26 Oct 2009 12:13:19 -0700 (PDT) X-Submission-Address: std-c++@netlab.cs.rpi.edu Date: Mon, 26 Oct 2009 15:26:52 CST Lines: 34 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-c3Xcrh8BNleZZ2+wkXK/m4nDWywH4cgTIWP4VL/KcIVygVlcKATJqXC0Pj8QfPMMpsPtgT8nALUc25v!8lVkLLy+DEAhkgG74oqG9OkrVyPwWBUOBCJI0ysuMgfjarzWAuGPPsURfKG5V5UrstimLNltkNLh!L94zBD8+xixdGTg5numia3/qKw== X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Xref: g2news2.google.com comp.std.c++:1577 On 26 Okt., 20:14, Saeed Amrollahi wrote: > I have a question about complex numbers in standard library. Why there > are both complex::real/imag > member functions and std::real/imag global funcctions? consider: > complex cd(1,2); > double r = cd.real(); > r = real(cd); > double i = cd.imag(); > i = imag(cd); > > >From point of OO view, it is obvious the real() and imag() should be > > part of member functions. > What is the benefit of global ones? The member functions are natural for a language with classes, like C++, therefore the member functions exist. The free function real and imag exist to match the free functions of C99 in their *generic* forms from 7.22 . With C++0x on all generic C99 complex functions will have a pendant in (Nearly all: fabs is missing because of LWG defect 595). HTH & Greetings from Bremen, Daniel Kr�gler -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]