Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!purdue!decwrl!ie0013.dec.com!vilot
From: vilot@ie0013.dec.com (Michael J. Vilot)
Newsgroups: comp.lang.c++
Subject: Re: using references vrs. pointers
Message-ID: <8901271426.AA26362@decwrl.dec.com>
Date: 27 Jan 89 17:28:00 GMT
Organization: Digital Equipment Corporation
Lines: 29

>   However, I seem to have no way of initializing
> a reference to refer to nothing, or testing if it refers to nothing (akin
> to a pointer to NULL).

Any reference must be initialized ("The C++ Programming Language", p. 56).
You can borrow a trick from Ada programmers: define a null object for any class
where such an object is sensible.  The you can declare references as alternate 
names for it:

class foo {
  int value;
  // ...
public:
  foo();
  foo(foo&);			// X(X&) initializer
  // ...
};

 foo NULL_FOO;

f() {
  foo& bar = NULL_FOO;
}

Hope this helps,

Mike Vilot			Self-employed.  Consulting at:
e-mail:	       			vilot%csdpie.dec@decwrl.dec.com
when that fails:    		(508)467-3631 [for now]