سلام,

کدی که مدرس نوشتن رو اینجا گذاشتم , امیدوارم مفید باشه.

نکته : ین پست به عنوان ‘نکته و تجربه' درج شده است

<?php
class BasketCost
{
    public function getCost()
    {
        return 15000;
    }
    public function getDescription()
    {
        return self::class;
    }
    public function getTotalCost()
    {
        return self::getCost();
    }
    public function getDetails()
    {
        return [
            self::getDescription() => self::getCost()
        ];
    }
}
class BasketWithShipping extends BasketCost
{
    public function getCost()
    {
        return 10000;
    }
    public function getDescription()
    {
        return self::class;
    }
    public function getTotalCost()
    {
        return parent::getCost() + self::getCost();
    }
    public function getDetails()
    {
        return parent::getDetails() + [
            self::getDescription() => self::getCost()
        ];
    }
}
class BasketWithTax extends BasketCost
{
    public function getCost()
    {
        return parent::getCost() * 0.09 ;
    }
    public function getDescription()
    {
        return self::class;
    }
    public function getTotalCost()
    {
        return parent::getCost() + self::getCost();
    }
    public function getDetails()
    {
        return parent::getDetails() + [
            self::getDescription() => self::getCost()
        ];
    }
}
$obj = new BasketWithTax;
//echo $obj->getDescription();
var_dump($obj->getDetails());
var_dump($obj->getTotalCost());