_unset()这是如何了

class Person {<br />		private $name;<br />		private $age;<br />		private $sex;<br />		//2. 构造方法		//作用: 给对象属性初始值<br />		function __construct($name='', $age='0', $sex='男'){	<br />			$this->name=$name;<br />			$this->age=$age;<br />			$this->sex=$sex;<br />		}<br />		private function __set($proName, $proValue){<br />			if($proName == 'age'){<br />				if($proValue<0 || $proValue>100){<br />					echo  '设置的年龄不合法';<br />					return;<br />				}else{<br />					 $this->$proName=$proValue;<br />					echo $this->age.'<br />';<br />				}<br />			}<br />		}<br />		private function __get($proName){<br />			if($proName == 'age'){<br />				echo ($this->$proName-20).'<br />';<br />			}<br />		}<br />		private function __isset($proName){<br />			if(isset($this->$proName)){<br />				echo $this->$proName.'存在<br />';<br />				return;<br />			}<br />				echo $proName.'不存在<br />';<br />		}<br />		private function __unset($proName){<br />			unset($this->$proName);<br />		}<br />		function say(){<br />			echo 'name........'.$this->name.'|age.........'.$this->age.'|sex..........'.$this->sex.'<br />';<br />		}<br />		function __destruct(){<br />		}<br />	}<br />	$p1 = new Person('yeteng', 26, '男');<br />	$p2 = new Person('yeben', 28, '男');<br />	$p3 = new Person('wenjing', 40, '女');<br />	$p1->age=99;		//自动触发__set<br />	$p1->age;				//自动触发__get<br />	isset($p1->name);//自动触发__isset<br /><br />	unset($p1->age);	//自动触发__unset<br />	$p1->say();