From 6795529356137134868 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,b3e3d077abe0c9b3 X-Google-Attributes: gidf78e5,public From: phalpern@truffle.ma.ultranet.com (Pablo Halpern) Subject: Re: Count signature Date: 1998/05/19 Message-ID: <35619a8d.8526337@news.ma.ultranet.com>#1/1 X-Deja-AN: 354695872 Content-Transfer-Encoding: 7bit Approved: stephen.clamage@sun.com (comp.std.c++) References: <6j0bmk$m0v@bgtnsc03.worldnet.att.net> <6j6bro$kok$1@nnrp1.dejanews.com> X-Ultra-Time: 19 May 1998 14:57:17 GMT Mime-Version: 1.0 Originator: clamage@taumet X-NNTP-Posting-Host: truffle.ultranet.com X-UID: 0000000001 X-Status: $$$T Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@ultra.net Organization: UltraNet Communications, Inc. http://www.ultranet.com/ Newsgroups: comp.std.c++ dietmar.kuehl@claas-solutions.de wrote: > > template > typename iterator_traits::size_type > count(It begin, It end, T const &val); > >The reason for the original version was simply that at this time there was >apparently no way to determine the size_type associated with the iterator. >Thus, the user was required to pass an object of appropriate type. With >'iterator_traits' the interface could be made safer (ie. the user cannot mess >up the type of the count anymore) and more convenient. The adapted SGI (and I think ObjectSpace) libraries have both versions, depending on the capabilities of your compiler. I think this is wrong-headed. For compilers that can't support traits classes, I think the better definition is: template unsigned long count(It begin, It end, T const &val); This allows users of slightly outdated compilers to use the newer calling convention without worrying about changing it when they upgrade compilers. The only time unsigned long is inappropriate is if you define your own size type which is larger than unsigned long. If you are doing that kind of thing, then I doubt the older compilers will be up to the task anyway. So lets just keep it simple for the 99% case. Anybody from the SGI adaptation effort listening? When I teach STL on older compilers, I provide a header file that defines count() as above and defines distance() similarly. It makes it easy to compile my lab solutions with both old and new compilers. BTW, I also get around the std:: namespace problem by using adding the -Dstd= option to compiler commands for most compilers. This causes std::cout to be preprocessed into just ::cout, which works great for compilers without namespaces. ------------------------------------------------------------- Pablo Halpern phalpern@truffle.ultranet.com I am self-employed. Therefore, my opinions *do* represent those of my employer. [ 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://reality.sgi.com/austern_mti/std-c++/faq.html ]