笔记一：看书学设计模式

<?php
class CartLine
{
    public $price;
    public $num;

    public function total()
    {
        return $this->num * $this->price;
    }
}

class Cart
{
    protected $sale = 0.8;
    protected $lines = array();

    public function addLine($cart)
    {
        $this->lines[] = $cart;
    }

    public function calcTotal()
    {
        $total = 0;
        foreach ($this->lines as $line) {
            $total+= $line->total();
        }
        $total = $this->calcSaleTotal($total);
        return $total;
    }

    public function calcSaleTotal($amount)
    {
        return $amount * $this->sale;
    }
}

$obj1 = new CartLine();
$obj1->price = 100;
$obj1->num = 2;
$obj2 = new Cart();
$obj2->addLine($obj1);
echo $obj2->calcTotal();

忘记一切面向对象，重新学习，体会了一下分块设计原则手写了一下，购物车的打折设计