[c-prog] allocating stack?? can u explain?

[Indika Bandara]

is this ok? this works sometimes

1)
func(int i)
{
char buf[i];
// access buf until i

}
usage:
func(5);


2)
func()
{
int i = 5;
char buf[i];
// access buf until i

}


will these not produce segfaults? then why?