From 1079747066426693659 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,de99e5c46dfe5a28 X-Google-Attributes: gidf78e5,public From: "Ross Smith" Subject: Re: Multiple declarations in for loop? Date: 1998/05/20 Message-ID: <6jsv8o$q03$1@newsource.ihug.co.nz>#1/1 X-Deja-AN: 354870532 Approved: Fergus Henderson Content-Transfer-Encoding: 7bit References: <35608CBB.2571@lehman.com> X-Original-Date: Wed, 20 May 1998 09:58:35 +1200 Content-Type: text/plain; charset="iso-8859-1" X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2106.4 Organization: The Internet Group X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUANWJ9PuEDnX0m9pzZAQExYgF/YcsugsddlAQtgOEZieHdTnFHM/Lq6Wsn nFMd03dR6/7rrxuGXC1//lTPcwJH1Ag2 =ie2a Mime-Version: 1.0 Newsgroups: comp.std.c++ Cristian Georgescu wrote in message <35608CBB.2571@lehman.com>... >Does the language allow the definition of multiple variables in a for >loop? > >F.I.: the compiler I am using (VC5.3) is accepting the following: > >int j=0; >for (int i=0; i<10,j<10; i++, j++) >{ > //... >} It accepts it, but I bet it isn't doing what you think it is. The comma operator means "evaluate the LHS, discard the result, then evaluate the RHS". Your termination clause, "i<10,j<10", is equivalent to plain "j<10". I'm surprised the compiler didn't give a warning about an unsed expression. (In the above loop the result is the same because both variables are being incremented together, unless there's code inside the loop that changes i or j.) >but does not accept the following: > >for (int i=0, int j=0; i<10,j<10; i++, j++) >{ > //... >} > >Is this in the standard or it is just a compiler bug? It's standard. You can't join declarations with the comma operator. -- Ross Smith ................................... mailto:ross.s@ihug.co.nz .............. The Internet Group, Auckland, New Zealand .............. "Remember when we told you there was no future? Well, this is it." -- Blank Reg --- [ 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 ]