class A { private $v1 = 1; public $v2 = 2; protected $v3 = 3; public function m1($n) { echo $n; echo "\n"; } } class B extends A { public $v4 = 4; public function m2($n) { echo $this->v4; echo "\n"; echo $this->v3; echo "\n"; } } $oa1 = new A(); $oa1->m1(1); $ob1 = new B(); $ob1->m2(1); echo "\n"; ?>