if (print("Hello World")) {
  print "1";}

$ducks = "12 ducks and 13 ducklings";
$result = $ducks + 10;
var_dump($result);

$array = array(
  'elephant' => 1,
  'tiger' => 0,
  'cat' => 1
);
var_dump(in_array('mouse', $array));

var_dump(empty($x));
var_dump(is_null($x));
var_dump(isset($x));
 

var_dump(empty($x));