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From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: assignment
Message-ID: <10891@alice.UUCP>
Date: 2 Jun 90 19:13:53 GMT
References: <4628@ethz.UUCP> <2666CD5A.1964@paris.ics.uci.edu>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 34

In article <2666CD5A.1964@paris.ics.uci.edu>, schmidt@crimee.ics.uci.edu (Doug Schmidt) writes:

> void operator= (deriv &d)
> {
>   // first initialize the base class part using base::operator =
>   *(base *)this = d;
>   k = d.k
> }

A slightly more elegant formulation:

	deriv& operator= (const deriv &d)
	{
	  // first initialize the base class part using base::operator =
	  (base&) *this = d;
	  k = d.k;
	  return *this;
	}

It is good practice for assignment-like operators to return their
left operand as a reference, to allow assignments to be chained and
for consistency with the built-in assignments.

It is important for operands that are written as references only to
forestall needless copying to be written as constant references.

I prefer the formulation `(base&) *this' to `*(base*) this' out of
a general desire to avoid explicit use of pointers when not really
necessary.

And, of course, the assignment to `k' needs a semicolon at the end  :-)
-- 
				--Andrew Koenig
				  ark@europa.att.com