getal 'sorteren'

<?php
				$lengte = strlen($getal);
				
				$getal[$lengte] = 1;
				$getal[$lengte + 1] = 3;
				sort($getal);
?>

<?php
				$lengte = strlen($getal);
 
				$getal[$lengte] = 1;
				$getal[$lengte + 1] = 3;
				sort($getal);
?>

<?
$arr = array(2,4);
$arr[] = 3;
$arr[] = 1;

echo implode("",sort($arr));
?>

<?
$arr = array(2,4);
$arr[] = 3;
$arr[] = 1;
 
echo implode("",sort($arr));
?>

<?
$nr = 24;
$arr = str_split($nr);
$arr[] = 3;
$arr[] = 1;

echo implode("",sort($arr));
?>

<?
$nr = 24;
$arr = str_split($nr);
$arr[] = 3;
$arr[] = 1;
 
echo implode("",sort($arr));
?>