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From: nagle@well.sf.ca.us (John Nagle)
Newsgroups: comp.lang.c++
Subject: Operator "++" applied to enumeration types.
Summary: Is "++" allowed for enumeration types?
Keywords: Zortech ++ enumeration
Message-ID: <23651@well.sf.ca.us>
Date: 17 Mar 91 08:31:00 GMT
Distribution: comp
Lines: 28


     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.

     Actually, increment and decrement on enumeration types make more
sense than allowing addition of two values of the same enumeration 
type.  Consider

	enum color_t {red,blue,green,yellow};
	color_t lamp1, lamp2;
	int i;

	lamp1 = red;			// OK
	lamp1++;			// reasonable
	lamp1 = red + green;		// silly,hould be an error
	lamp1 = red + 1;		// better
	i = lamp1 - lamp2;		// difference is logically an integer

But this is probably too radical for C++.




	

					John Nagle