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From: ark@alice.att.com (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: Operator "++" applied to enumeration types.
Keywords: Zortech ++ enumeration
Message-ID: <20065@alice.att.com>
Date: 18 Mar 91 18:40:38 GMT
References: <23651@well.sf.ca.us>
Reply-To: ark@alice.UUCP ()
Distribution: comp
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 16

In article <23651@well.sf.ca.us> nagle@well.sf.ca.us (John Nagle) writes:

>      Is the operator "++" permitted on enumeration types in C++?
> Zortech C++ 2.1 rejects it as a request for an invalid type conversion.
> Zortech C 2.1 is quite happy with it, leading me to suspect this is
> policy, not a bug.  But Strostrup's book is silent on the subject.

Not quite.

In effect, ++x is equivalent to (x=x+1), with all the conversion rules
that that implies.  Now, if x is of an enumeration type, x+1 is an
int, and there is no conversion from int to enum without an explicit
cast.  Therefore ++ cannot apply to an object of enumeration type.
-- 
				--Andrew Koenig
				  ark@europa.att.com