page34类的继承

好些时候没再写过面向对象了，现在忘了好多东西，经常不用所以忘记，没办法只能再重新看看了。只可惜在工作中不怎么用面向对象，不然也不能这样啊，以后在工作中还是不怎么用，以后又什么都不会了，如此恶性循环。。。

<?php
/**
 * Page34 Class Extends
 * @authors haidong (admin@zhe700.net)
 * @date    2015-03-25 10:13:29
 * @version $Id$
 */

class Product{
    public $title;
    public $producerMainName;
    public $producerFirstName;
    public $price;
    public function __construct($title,$producerMainName,$producerFirstName,$price){
        $this->title = $title;
        $this->producerMainName = $producerMainName;
        $this->producerFirstName= $producerFirstName;
        $this->price = $price;
    } 
    public function getProducer(){
        return "{$this->producerFirstName}" . "{$this->producerMainName}";
    }
    public function getSummaryLine(){
        $base = "{$this->title} ({$this->producerFirstName} {$this->producerMainName})";
        return $base;
    }
}
class CdProduct extends Product{
    public $playLenth;
    public function __construct($title,$producerMainName,$producerFirstName,$price,$playLenth){
        parent::__construct($title,$producerMainName,$producerFirstName,$price);
        $this->playLenth = $playLenth;
    }
    public function getSummaryLine(){
        $base = "{$this->title} ({$this->producerFirstName} {$this->producerMainName})";
        $base .= "play time ({$this->playLenth})";
        return $base;
    }
}
class BookProduct extends Product{
    public $numPages;
    public function __construct($title,$producerMainName,$producerFirstName,$price,$numPages){
        parent::__construct($title,$producerMainName,$producerFirstName,$price);
        $this->numPages = $numPages;
    }
    public function getSummaryLine(){
        $base = parent::getSummaryLine();//只是对父类功能的丰富，前面功能 相同，直接调用就好了，没必要再重新写
        $base .= "page numbers ({$this->numPages})";
        return $base;
    }
}
$cd = new CdProduct('CD','John','Smith',79,90);
echo $cd->getSummaryLine();
$book = new BookProduct('Book','Bob','zhang',49,360);
echo $book->getSummaryLine();

代码很简单，功能很简单。主要是想记住在子类丰富父类的时候，可以调用父类的构造函数进行初始化，不然的话，自己的数据是不完整的。还有就是对getSummaryLine只是对父类方法的丰富，所以没必要重新写，直接调用父类的方法就好了，就可以轻而易举的实现。以后写代码的时候还是需要好好考虑应该怎么把代码写的更优雅。过往匆匆里都是我的成长，我在此成长！