Give this a try and you'll see the problem. It's related to the "destroying the array" solution earlier.

my @array= ( 1 .. 9 );
my $index;
while( $index < $#array+1 ) {
    my $last = pop(@array);
    print "$index < ", $#array+1, "\n";
    $index++;
}
[download]

You shouldn't really update your original post; it gets confusing then because the thread of replies start to look bizarre or wrong. Better to reply with a new post.