I am trying to get highest number from `array`. But not getting it. I have to get highest number from the array using `for` loop.

```
<?php
$a =array(1, 44, 5, 6, 68, 9);
$res=$a[0];
for($i=0; $i<=count($a); $i++){
    if($res>$a[$i]){
        $res=$a[$i];
    }
}
?>

```

I have to use `for` loop as i explained above. Wat is wrong with it?