php类知识点滴---类的实例化，构造函数，继承初步

• 实例化类----黑科技用法，通过字符串来实例化

class coach
{
    public function __construct()
    {
        echo "欢迎光临北武堂"."\n";
    }
    public function slogan()
    {
        echo "吼吼~哈哈~"."\n";
    }
}
$wenwa = 'coach';//字符串对应了coach类
$duwa = new $wenwa;
$duwa->slogan();

• 构造函数

<?php
class mylove
{
    public $name="陈培昌";
    public function __construct()
    {
        echo "喜欢练搏击的弟弟"."\n";
    }
    public function showmyname()
    {
        echo "获取到的名字是:".$this->name."\n";
    }
}
$cpc = new mylove();
$cpc->showmyname();
?>

结果：

　　喜欢练搏击的弟弟
　　获取到的名字是:陈培昌

•  继承(与python不同，php是单一继承语言，也就是一个类只能有一个父类)

父类代码如下：
class coach
{
    public $master = "老张";
    protected $lover = "丁大锅";
    private $lovegame = "SM";
    public function slogan()
    {
        echo "吼吼~哈哈~"."\n";
    }
}

定义父类coach的子类cpc，继承使用关键词extends
class cpc extends coach
{
    public function __construct()
    {
        //$this->master = $master;
        echo "我的师父是".$this->master."__我爱".$this->lover."__喜欢玩"."\n";
    }

    public function self_introduce($name,$age)
    {

        echo "hello~my name is ".$name."今年芳龄".$age."\n";
    }
}
$cpc = new cpc();

$cpc->slogan();

输出结果：

吼吼~哈哈~
hello~my name is 陈培昌今年芳龄21

点评：哇啊哦~这么厉害，子类cpc里没有定义slogan方法居然可以调用！正是继承的魔力之所在！