<?php
class Product {
    protected $productid;
 
    public function getPrice() {
        return NULL; // or 0 or whatever default you want
    }
}
 
class Toothbrush extends Product {
    public function getPrice() {
        return 5; // in USD
    }
}
 
class Chainsaw extends Product {
    public function getPrice() {
        return 1000; // in USD
    }
}
 
 
$toothbrush = new Toothbrush();
$chainsaw = new Chainsaw();
var_dump($toothbrush->getPrice());
var_dump($chainsaw->getPrice());
?>

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