<?php
 
class ShopProduct{
  public $title = "prod";
  private $price = 0;
 
  function __construct($title, $price){
    $this->title = $title;
    $this->price = $price;
  }
 
  public function getPrice(){
    return $this->price;
  }
}
 
class Saller{
  function sale(ShopProduct $product, $sale){
    return $product->getPrice() + $sale;
  }
}
 
$product = new ShopProduct("dd", 50);
$saller  = new Saller();
 
echo $saller->sale($product, 0.1);
echo "<br />".$saller->sale($product, 0);

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