__construct

class User {
    public $username;
    public $friends = ['Tom','David'];

    function __construct($name) {
        $this->username = $name;
        // print "In BaseClass constructor\n";
    }
    
    public function addFriend($friend_name) {
        $this->friends[] = $friend_name;
    }
}
$user1 = new User('George');
echo $user1->username;