Online PHP editor | output for BOhkF

<?php class User { private $firstname; private $lastname; private $age; public function __contruct() { $this->firstname = null; $this->lastname = null; $this->age = null; } public function __set($property, $value) { $property = trim(strtolower($property)); if (!property_exists($this, $property)) { throw new Exception("$property does not exists"); } if( !isset($value) && empty($value)) { throw new Exception("$property Can not be NULL or EMPTY"); } switch($property) { case "firstname": case "lastname": if(!is_string($value)) { throw new Exception("$property must be a String"); } $this->$property = $value; break; case "age": if(!is_int($value)) { throw new Exception("TypeError : $property must be an Integer Value"); } $this->$property = $value; break; default: throw new Exception("Invalid Exception."); break; } } public function __get($property) { if(!property_exists($property)) { throw new Exception("Invalid Arguments: $property Does not Exists"); } return $this->$property; } } $user = new User(); $user->set("firstname", "Zia"); echo $user->get("firstname");