Path: utzoo!attcan!uunet!snorkelwacker!usc!zaphod.mps.ohio-state.edu!rpi!batcomputer!lijewski
From: lijewski@batcomputer.tn.cornell.edu (Mike Lijewski)
Newsgroups: comp.std.c++
Subject: Re: the most dissatisfying part of c++
Message-ID: <10599@batcomputer.tn.cornell.edu>
Date: 31 Jul 90 17:44:43 GMT
References: <27634@netnews.upenn.edu>
Reply-To: lijewski@tcgould.tn.cornell.edu (Mike Lijewski)
Organization: Cornell National Supercomputer Facility
Lines: 23

In article <27634@netnews.upenn.edu> limsoon@saul.cis.upenn.edu.UUCP (Limsoon Wong) writes:
 
>the program below is a contrived one.   it cannot  be compiled.
>the reason is a type fault. however, it exhibits a very central
>characteristic of update.    something should be  done to allow
>this kinds of programs.	   			    ---limsoon.

I disagree completely that such programs should be allowed.  Since test()
returns a `a&', basically what you are asking is that there be a implicit
conversion from a base class to a derived class.  No way should this be
allowed.  If you really want the below program to work, one possibility
would be to add the following constructor definitions to the class
declaration of b:

	 b() {};
	 b(a) {};
 

-- 
Mike Lijewski  (H)607/277-0394 (W)607/254-8686
Cornell National Supercomputer Facility
ARPA: mjlx@eagle.cnsf.cornell.edu  BITNET: mjlx@cornellf.bitnet
SMAIL:  1122 Ellis Hollow Rd. Ithaca, NY  14850