类成员的访问方式和权限_PHP教程

＜?php    class Widget    {        private $name;        private $price;        private $id;        public function __construct($name, $price)        {            $this->name = $name;            $this->price = floatval($price);            $this->id = uniqid();        }        //checks if two widgets are the same 检查两个widget是否相同        public function equals($widget)        {            return(($this->name == $widget->name)AND                ($this->price == $widget->price));        }    }    $w1 = new Widget('Cog', 5.00);    $w2 = new Widget('Cog', 5.00);    $w3 = new Widget('Gear', 7.00);    //TRUE    if($w1->equals($w2))    {        print("w1 and w2 are the same<br>n");    }    //FALSE    if($w1->equals($w3))    {        print("w1 and w3 are the same<br>n");    }    //FALSE, == includes id in comparison    if($w1 == $w2) //不等,因为ID不同    {        print("w1 and w2 are the same<br>n");    } ?＞

＜?php    class Widget    {        private $name;        private $price;        private $id;        public function __construct($name, $price)        {            $this->name = $name;            $this->price = floatval($price);            $this->id = uniqid();        }        //checks if two widgets are the same        public function equals($widget)        {            return(($this->name == $widget->name)AND                ($this->price == $widget->price));        }        protected function getName()        {            return($this->name);        }    }    class Thing extends Widget    {        private $color;        public function setColor($color)        {            $this->color = $color;        }        public function getColor()        {            return($this->color);        }        public function getName()        {            return(parent::getName());        }    }    $w1 = new Widget('Cog', 5.00);    $w2 = new Thing('Cog', 5.00);    $w2->setColor('Yellow');    //TRUE (still!) 结果仍然为真    if($w1->equals($w2))    {        print("w1 and w2 are the same<br>n");    }    //print Cog 输出 Cog    print($w2->getName()); ?＞