Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!lll-tis!mordor!sri-spam!rutgers!bellcore!faline!ulysses!allegra!alice!ark
From: ark@alice.UUCP
Newsgroups: comp.lang.c
Subject: Re: interesting program
Message-ID: <7664@alice.UUCP>
Date: 30 Jan 88 14:59:12 GMT
References: <19@berick.UUCP>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 25
Summary: there is no right answer

In article <19@berick.UUCP>, jeffl@berick.UUCP writes:
> What does the following program print?  (I know of at least one
> program that prints the wrong answer).

> {
> 	int k = 4;
> 	k = k++;
> 	printf("and the answer is %d\n", k);
> 	exit(0);
> }

Saying "the wrong answer" implies that there is a right answer.
In fact, the result of this program is undefined, because the
implementation is permitted to

	fetch k
	increment k
	store old value of k in k

(in which case the result is 4), or

	fetch k
	store old value of k in k
	increment k

(in which case the result is 5).