- array_push: documentation ( source)
- array_shift: documentation ( source)
- implode: documentation ( source)
- array_fill: documentation ( source)
<?php
$cnt = 5;
$array = array_fill(1, ($cnt), '-');
for($i=1;$i<($cnt+1);$i++){
array_shift($array);
array_push($array, $i);
echo implode(" ", $array);
echo "\n";
}