Path: utzoo!attcan!uunet!yale!mfci!karzes
From: karzes@mfci.UUCP (Tom Karzes)
Newsgroups: comp.lang.c
Subject: Re: Problem with ()?():() as ending test in for-loop
Message-ID: <877@m3.mfci.UUCP>
Date: 26 May 89 19:16:30 GMT
References: <1200@liszt.kulesat.uucp> <17722@mimsy.UUCP> <779@attila.WEITEK.COM>
Sender: karzes@mfci.UUCP
Reply-To: karzes@mfci.UUCP (Tom Karzes)
Organization: Multiflow Computer Inc., Branford Ct. 06405
Lines: 14

In article <779@attila.WEITEK.COM> kens@attila.WEITEK.COM (Ken Stanley) writes:
}The specific example: "((n % 10) != 0 && k > 2) || n < 100" works because
}when n = 100, (n % 10) == 0 and ! (n < 100).  However, if the loop increment
}were 3 instead of 1, it would not.
}...
}... these two statements are identical:
}
}for (n = 1; ((n % 10) != 0 && k > 2) || n < 100; n++)
}for (n = 1; ((n % 10) ? (k > 2) : (n < 100); n++)

No, these two statements are not identical, even in this context.  Consider
the case where n is 11 and k is 1.  The original ?: expression evaluates
to 0, whereas the incorrect alternate form evaluates to 1.  (By the way,
the second expression shown above has unbalanced parentheses.)