The difference between the three data types in php5 classes

/**
 * parent 　Only public or protected methods in the parent class can be called, and attributes in the parent class cannot be called
 * self 　All data in the parent class except private type methods and attributes can be called
*/
class User{
    public $name;
    private $passwd;
    protected $email;
    public  function __construct(){
        //print __CLASS__." ";
        $this->name= 'simple';
        $this->passwd='123456';
        $this->email = 'test123@163.com';
    }
    public function show(){
        print "good ";
    }
    public function inUserClassPublic() {
        print __CLASS__.'::'.__FUNCTION__." ";
    }
    protected  function inUserClassProtected(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }
    private function inUserClassPrivate(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }
}
class simpleUser extends User {
    public function __construct(){
        //print __CLASS__." ";
        parent::__construct();
    }

    public function show(){
        print $this->name."//public ";
        print $this->passwd."//private ";
        print $this->email."//protected ";
    }

    public function inSimpleUserClassPublic() {
        print __CLASS__.'::'.__FUNCTION__." ";
    }

    protected function inSimpleUserClassProtected(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }

    private function inSimpleUserClassPrivate() {
        print __CLASS__.'::'.__FUNCTION__." ";
    }
}
class adminUser extends simpleUser {
    protected $admin_user;
    public function __construct(){
        //print __CLASS__." ";
        parent::__construct();
    }

    public function inAdminUserClassPublic(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }

    protected function inAdminUserClassProtected(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }

    private function inAdminUserClassPrivate(){
        print __CLASS__.'::'.__FUNCTION__." ";
    }
}
class administrator extends adminUser {
    public function __construct(){
        parent::__construct();
    }
}
/**
 * In an instance of a class, only public properties and methods can be called through instantiation
*/
$s = new administrator();
print '-------------------';
$s->show();
?>