<?php
abstract class islemler
{
public $sayi1 = 50;
public $sayi2 = 20;
public function topla()
{
echo $this->sayi1 + $this->sayi2;
}
public abstract function fark();
}
class islemler2 extends islemler
{
public function fark()
{
}
}
$islem = new islemler2();
$islem -> topla();
?>