From -5310358261727333260 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,5e69b3c02624e7d0 X-Google-Attributes: gidf78e5,public From: "Andrew R. Thomas-Cramer" Subject: Re: A C++ asymmetry Date: 1999/09/14 Message-ID: <37de5f2f$0$91176@news.execpc.com>#1/1 X-Deja-AN: 525022348 Approved: Fergus Henderson References: X-Original-Date: Tue, 14 Sep 1999 09:45:22 -0500 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 X-Complaints-To: news@news.unimelb.edu.au X-Trace: ariel.ucs.unimelb.edu.au 937324777 1080 128.250.37.153 (14 Sep 1999 15:59:37 GMT) Organization: ExecPC Internet - Milwaukee, WI X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUAN95w4OEDnX0m9pzZAQFIPgF7BAqhpe1mkQDXnmqQCGEdMGMrodS8T5i3 f7hXQPp0zjCuJ9iKCmuz0BgC7Miv4go7 =I9yl NNTP-Posting-Date: 14 Sep 1999 15:59:37 GMT Newsgroups: comp.std.c++ 1. Compatibility with C. One of C++'s goals is backwards compatibility with C. ANSI C structs implicitly support copy and assignment, even if someone's written one or more initialization functions for the struct. The present rule thus makes classes behave similarly to C structs. 2. Parallelism If copy constructors were created implicitly only if _no_ other constructors were defined, either the assignment operator would either need to follow the same rule, or not. If it did, defining a single constructor explicitly would turn off the implicit assignment operator, which seems an unnatural dependency. If it didn't, it would not satisfy parallelism with the copy constructor, and a particular class could have an implicit assignment operator but not an implicit copy constructor. 3. Utility Mr. Glassborow covered this in a previous article. --- [ 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 ]