Path: utzoo!attcan!uunet!mcvax!ukc!strath-cs!glasgow!orr
From: orr@cs.glasgow.ac.uk (Fraser Orr)
Newsgroups: comp.lang.c++
Subject: A very simple question.
Message-ID: <1606@crete.cs.glasgow.ac.uk>
Date: 2 Sep 88 16:22:07 GMT
Reply-To: orr%cs.glasgow.ac.uk@nss.ucl.ac.uk (Fraser Orr)
Organization: Comp Sci, Glasgow Univ, Scotland
Lines: 43

There is probably a very simple answer to this question, unfortunately
I don't know it!

I'm trying to create an object with, as some of it's private
data members, other objects. Now these data members are objects
with constructors, as is the object containing it.
Unfortunately this doesn't seem to be allowed (data members may not
have constructors).
As an example ...

class a {
	int b ;
public:
	a ( int c) 
	{
		b=c ;
	} ;
} ;

class d {
	a NeedsCtor (1) ; // This line is illegal
public:
	d (int e )
	{
		...
	} ;
} ;


Is it necessary to have a constructor with no parameters for every
object that may be used as a data member? 
I know that it is also possible to have a pointer to a as the data
member, and then do a new in d's constructor, but I thought we had
got away from all that tacky stuff when we moved to C++.

I'm probably missing something obvious, so I would appreciate any
enlightenment.

Thanks,

==Fraser Orr ( Dept C.S., Univ. Glasgow, Glasgow, G12 8QQ, UK)
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