//已經定義以下php類
class People{
    static $version = "1.02beta";
    private $age;
    
    public function m($key,$value=NULL){
        if($value == NULL){
            return $this->key;
        }else{
            $this->key = $value;
        }
    }
}
//1、用echo輸出People的版本號
echo People::$version;

echo "<br/>";

//2、實例化一個People,叫$jack,並給他的age賦值為50
$jack = new People();
$jack->m("age",50);
echo $jack->m("age");
 

　　

/**
 * 繼承People的子類Child,Child在實例化時,會自動echo父類的版本號。
 */

/**People.class.php文件**/
class People{
    static $version = "1.02beta";
    private $age;
    
    public function m($key,$value=NULL){
        if($value == NULL){
            return $this->key;
        }else{
            $this->key = $value;
        }
    }
}

/**Child.class.php文件**/
require "People.class.php";
class Child extends People{
	public function __construct(){
		echo parent::$version;//輸出父類版本號
	}
}

//輸出父類版本號
new Child();

PHP工程師筆試題