PHP 之 OOP继承

<?php

class Person {
	var $name;//protected
	var $sex;
	var $age;
	
	function __construct($name = "", $sex = "男", $age = 22) {
		$this->name = $name;
		$this->sex = $sex;
		$this->age = $age;
	}
	
	function say() {
		echo $this->name . "在说话<br/>";
	}
	
	function run() {
		echo "在走路·<br/>";
	}
}

class Student extends Person {
	var $school;
	
	function __construct($name = "", $sex = "男", $age = 22,$school="") {
		parent::__construct($name,$sex,$age);
		$this->school = $school;
	}
	
	function study() {
		echo $this->name."正在".$this->school."学习<br/>";
	}
}

class Teacher extends Student {
	var $wage;
	
	function teaching() {
		echo $this->name."正在".$this->school."教学，每月工资为".$this->wage."<br/>";
	}
}

$teacher1 = new Teacher("kaifu","男",22);

$teacher1->school = "edu";
$teacher1->wage = 4000;

$teacher1->say();
$teacher1->study();
$teacher1->teaching();
?>

结果：

kaifu在说话
kaifu正在edu学习
kaifu正在edu教学，每月工资为4000