From -5837413223092588335 X-Google-Thread: f78e5,1130da7a3640a78c X-Google-Attributes: gidf78e5,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news2.google.com!news3.google.com!news.glorb.com!news.alt.net!comp-std-cpp-robomod!not-for-mail From: "Greg Herlihy" Newsgroups: comp.std.c++ Subject: Re: Deprecate the use of plain pointers as standard container iterators Date: 6 May 2006 17:40:01 GMT Organization: http://groups.google.com Lines: 52 Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <1146925399.228527.177770@j33g2000cwa.googlegroups.com> References: <1146830242.416436.272780@g10g2000cwb.googlegroups.com> <1146842605.957240.37860@i39g2000cwa.googlegroups.com> <445bb6ab$0$60786$157c6196@dreader1.cybercity.dk> <4c2kp3F13dairU1@individual.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Return-Path: X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) X-Original-To: std-c++@mailman.ucar.edu Delivered-To: std-c++@mailman.ucar.edu Delivered-To: std-c++@ucar.edu X-Trace: posting.google.com 1146925406 10980 127.0.0.1 (6 May 2006 14:23:26 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sat, 6 May 2006 14:23:26 +0000 (UTC) User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en) AppleWebKit/418 (KHTML, like Gecko) Safari/417.9.2,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: j33g2000cwa.googlegroups.com; posting-host=70.231.148.21; posting-account=JdllFQ0AAAC-QghphnHMZz5q0GHnzGUJ X-Virus-Scanned: amavisd-new at ucar.edu X-Virus-Scanned: amavisd-new at cs.mu.OZ.AU X-Virus-Scanned: amavisd-new at cs.mu.OZ.AU Xref: g2news2.google.com comp.std.c++:1798 Alf P. Steinbach wrote: > * Thorsten Ottosen: > > > > Please see > > > > http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1870.html#add-iterator-utilities-from-boost > > > > Titled "Crazy ideas", but they're not at all crazy. Change the title. > > Also, I think it would be a good idea to add inclusion of pi and e > constants in and/or . > > There is existing practice for pi: having M_PI in , but the > uppercase stems from the C heritage and may conflict with macro naming. > > Here's a list of constants from one very popular compiler: > > M_E e 2.71828182845904523536 > M_LOG2E log2(e) 1.44269504088896340736 > M_LOG10E log10(e) 0.434294481903251827651 > M_LN2 ln(2) 0.693147180559945309417 > M_LN10 ln(10) 2.30258509299404568402 > M_PI pi 3.14159265358979323846 > M_PI_2 pi/2 1.57079632679489661923 > M_PI_4 pi/4 0.785398163397448309616 > M_1_PI 1/pi 0.318309886183790671538 > M_2_PI 2/pi 0.636619772367581343076 > M_2_SQRTPI 2/sqrt(pi) 1.12837916709551257390 > M_SQRT2 sqrt(2) 1.41421356237309504880 > M_SQRT1_2 1/sqrt(2) 0.707106781186547524401 The POSIX technical standard defines these 13 symbolic constants in math.h (see X/Open CAE System Interfaces and Headers Issue 4, Version 2 pg. 780 from http://www.opengroup.org). Note that POSIX does not require that these symbols be defined as macros - so it would certainly be permissible to declare them as const doubles for a C++ compiler. And while the C++ standard could also add these (or similar) constants to math.h (or cmath), it's not likely gain much. Most C++ programs are compiled on POSIX compliant OSes today, which means that, as a practical matter, these symbols are already available to almost any C++ programmer who wishes to use them in a program. Greg --- [ 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 ]