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# [Frama-c-discuss] Problem with ACSL annotations

```Hello,

Le mar. 18 d?c. 2012 12:28:20 CET,
intissar mzalouat <intissar_mzalouat at yahoo.fr> a ?crit :

> /*@ requires \valid_range(queue,0,14);
> ??? ensures \result==0 ==> (\exists int i;0<=i<15 && ((\forall int j;
> 0<=j<15 && queue[i] > queue[j] )&&((queue[i]>=5) ||
> (queue[i]<=10)))); */ int find_array_max(int queue){
>
> I had some problems to write postconditions in ACSL for this function.

It would have helped if you had stated explicitely what your problems
were, but my guess is that
\forall int j; 0<=j<15 && queue[i]>queue[j]
should be replaced with
\forall int j; 0<=j<15 ==> queue[i]>queue[j]
The former says that for any int j, both 0<=j<15 and queue[i]>queue[j]
hold, which is trivially falsified by taking j == -1. The latter says
that for any int j between 0 and 15, we have queue[i]>queue[j].
More generally, the informal spec "for any x in P, Q holds" is
written \forall x; P ==> Q, while "there exists x in P such that Q
holds" is indeed written as what you've done: \exists x; P && Q.

Best regards,
--
E tutto per oggi, a la prossima volta.
Virgile

```