Path: utzoo!attcan!uunet!lll-winken!ames!killer!texbell!bellcore!faline!thumper!ulysses!andante!alice!shopiro
From: shopiro@alice.UUCP (Jonathan Shopiro)
Newsgroups: comp.lang.c++
Subject: Re: A question or two from a Beginner
Summary: Using friend operators
Message-ID: <8746@alice.UUCP>
Date: 13 Jan 89 16:02:53 GMT
References: <1001@elmgate.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill NJ
Lines: 27



Here is a program that should work.

struct X {
	X(char*);
	~X();
	int dummy;
};
int	operator==(const X&, const X&);
int foo(const X& x)
{
	return "abc" == x;
}

If operator==() were a member of X instead of a friend, it would not work,
since no coercion is done on the object for which a member function is
called.

Of course this is not very efficient, because an X object is created and
destroyed within foo.  It would be better to have an additional function

int	operator==(char*, const X&);
-- 
		Jonathan Shopiro
		AT&T Bell Laboratories, Warren, NJ  07060-0908
		research!shopiro   (201) 580-4229