Hello PHP 7

define_constant.php

<?php
define('ALLOWED_IMAGE_EXTENSIONS', ['jpg', 'jpeg', 'gif', 'png']);
var_dump(ALLOWED_IMAGE_EXTENSIONS);
?>

null_coalesce_operator.php

<?php
// Pre PHP 7 code
$username = isset($_GET['username']) ? $_GET['username'] : 'DEFAULT';

// PHP 7
$username = $_GET['username'] ?? 'DEFAULT';
echo $username;
?>

scalar_type_stricts.php

<?php
declare(strict_types=1);

function sumOfInts(int ...$ints){
    return array_sum($ints);
}

sumOfInts(2, '3', 4.1);

?>

//Output
PHP Fatal error:  Uncaught TypeError: Argument 2 passed to sumOfInts() must be of the type integer

spaceship_operator.php

<?php
var_dump('PHP 7' <=> 'PHP 5'); // int(1)

var_dump(123 <=> 456); // int(-1)

var_dump(['a', 'b'] <=> ['a', 'b']); // int(0)

?>