<?php

class mysingle

{

    private static $myinstance =null;

    private function __construct()

    {

    }

    private function  __clone()

    {

    }

    public static function createobject()

    {

        if (self::$myinstance==null)

        {

            self::$myinstance = new self();

        }

        return self::$myinstance;

    }

}

$thesingle = mysingle::createobject();

$anothersingle = mysingle::createobject();

echo ($thesingle===$anothersingle);

?>

<?php

class dingdaguo

{

     protected $observers = [];

     public function addobserver($myobserver)

     {

        $this->observers[] = $myobserver;

     }

     public function drink_cola()

     {

        foreach($this->observers as $observer)

        {

            $observer->persuade();

        }

     }

     public function delobsrver($observer)

     {

         $index = array_search($observer,$this->observers,);

         $this->observers=array_slice($this->observers,,$index);

     }

}

class coach

{

    public function __construct($name)

    {

        $this->name = $name;

    }

    public function persuade()

    {

        echo $this->name."说:别喝可乐了，都是甜的东西".PHP_EOL;

    }

}

$cpc = new coach("陈培昌");

$cj = new coach("程劲");

$dy = new dingdaguo();

$dy->addobserver($cpc);

$dy->addobserver($cj);

$dy->drink_cola();
echo "删除其中一个对象".PHP_EOL;
$dy->delobsrver($cj); 
$dy->drink_cola();

<?php

interface martial_trainning

{

    public function welcomeword();

    public function braziljudo();

    public function muaythai();

}

class xxd

{

    public function welcomeword()

    {

        echo "欢迎来到必图训练".PHP_EOL;

    }

}

class cj

{

    public function braziljudo()

    {

        echo "我是小烤肠，来跟我一起学巴西柔术吧".PHP_EOL;

    }

}

class cpc implements martial_trainning

{

    protected $myxxd = null;

    protected $mycj = null;

    public function __construct($xxd,$cj)

    {

        $this->myxxd = $xxd;

        $this->mycj = $cj;

    }

    public function welcomeword()

    {

        // TODO: Implement welcomeword() method.

        $this->myxxd->welcomeword();

    }

    public function braziljudo()

    {

        // TODO: Implement braziljudo() method.

        $this->mycj->braziljudo();

    }

    public function muaythai()

    {

        echo "我是小松鼠，跟我一起练习泰拳吧".PHP_EOL;

    }

}

$cj = new cj();

$xxd = new xxd();

$cpc = new cpc($xxd,$cj);

$cpc->braziljudo();

$cpc->welcomeword();

$cpc->muaythai();

?>

<?php

interface martial_trainning

{

    public function hoaring();

}

class xxd implements martial_trainning

{

    public function hoaring()

    {

        echo "诶斯~诶斯~".PHP_EOL;

    }

}

class cj implements martial_trainning

{

    public function hoaring()

    {

        echo "诶~嘿嘿".PHP_EOL;

    }

}

class cpc implements martial_trainning

{

    public function hoaring()

    {

       echo "嗷儿喂~嗷儿喂~";

    }

}

class mycoach

{

    protected $myobject = null;

    public function  __construct($whichobject)

    {

        $this->myobject = $whichobject;

    }

    public function hoaring()

    {

        $this->myobject->hoaring();

    }

}

$cpc = new cpc();

$mycoach = new mycoach($cpc);

$mycoach->hoaring();

echo PHP_EOL."===========换了一个类=============".PHP_EOL;

$cj = new cj();

$mycoach = new mycoach($cj);

$mycoach->hoaring();

?>