interesting program

[ark at alice.UUCP]

In article <19 at berick.UUCP>, jeffl at 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).