<?php 
header("content-type:text/html;charset=utf-8"); 
// BaseClass 
class pub { 
 public $tag_line = "腳本之家！"; 
 function display() { 
  echo $this->tag_line."<br/>"; 
 } 
} 
 
// 子類
class child extends pub { 
 function show(){ 
  echo $this->tag_line; 
 } 
} 
 
// 對(duì)象聲明
$obj= new child; 
 
// 輸出
echo $obj->tag_line."<br/>"; 
 
$obj->display(); 
 
$obj->show(); 
?>

<?php 
header("content-type:text/html;charset=utf-8"); 
// 基類
class pro { 
 protected $x = 500; 
 protected $y = 500; 
    
 // 實(shí)現(xiàn)減法 
 function sub() 
 { 
  echo $sum=$this->x-$this->y . "<br/>"; 
 }  
} 
 
// 子類-繼承類
class child extends pro { 
 function mul() //實(shí)現(xiàn)乘法
 { 
  echo $sub=$this->x*$this->y; 
 } 
} 
 
$obj= new child; 
$obj->sub(); 
$obj->mul(); 
?>

<?php 
header("content-type:text/html;charset=utf-8"); 
// 基類
class demo { 
 private $name="腳本之家！"; 
  
 private function show() 
 { 
  echo "這是基類的私有方法"; 
 } 
} 
 
// 子類
class child extends demo { 
 function display() 
 { 
  echo $this->name; 
 } 
} 
 
// 對(duì)象聲明
$obj= new child; 
 
// 出現(xiàn)異常---未捕獲錯(cuò)誤：調(diào)用私有方法demo：：show()
//$obj->show(); 
 
//出現(xiàn)異常--未定義的屬性：子級(jí)：：$name
$obj->display(); 
?>