<?php

class Authenticate {
    private $user;

    function __construct(User $user) {
        $this->user = $user;
    }

    function authenticate() {
        return true;
    }
}

class User {
    private $username;
    private $password;

    function __construct($username, $password) {
        $this->username = $username;
        $this->password = $password;
    }

    public function login() {
        $a = new Authenticate($this);
        return $a->authenticate();
    }
}

$U = new User('carress', 'carrots');

$U->login();


?>