_unset()这是如何了

class Person {

		private $name;

		private $age;

		private $sex;

		//2. 构造方法		//作用: 给对象属性初始值

		function __construct($name='', $age='0', $sex='男'){	

			$this->name=$name;

			$this->age=$age;

			$this->sex=$sex;

		}

		private function __set($proName, $proValue){

			if($proName == 'age'){

				if($proValue<0 || $proValue>100){

					echo  '设置的年龄不合法';

					return;

				}else{

					 $this->$proName=$proValue;

					echo $this->age.'
';

				}

			}

		}

		private function __get($proName){

			if($proName == 'age'){

				echo ($this->$proName-20).'
';

			}

		}

		private function __isset($proName){

			if(isset($this->$proName)){

				echo $this->$proName.'存在
';

				return;

			}

				echo $proName.'不存在
';

		}

		private function __unset($proName){

			unset($this->$proName);

		}

		function say(){

			echo 'name........'.$this->name.'|age.........'.$this->age.'|sex..........'.$this->sex.'
';

		}

		function __destruct(){

		}

	}

	$p1 = new Person('yeteng', 26, '男');

	$p2 = new Person('yeben', 28, '男');

	$p3 = new Person('wenjing', 40, '女');

	$p1->age=99;		//自动触发__set

	$p1->age;				//自动触发__get

	isset($p1->name);//自动触发__isset



	unset($p1->age);	//自动触发__unset

	$p1->say();