錯誤：類必須聲明爲抽象或實現其餘方法

Question

我有一個類實現了幾個抽象方法。當我繼承了該類我得到以下致命錯誤消息：

Class CI_Controller_Rest contains 6 abstract methods and must therefore be declared abstract or implement the remaining methods 

與抽象方法的類：

class CI_Controller_Rest extends CI_Controller { 
    public function __construct() { 
     parent::__construct(); 
    } 

    abstract public function index(); 

    abstract public function get(); 

    abstract public function head(); 

    abstract public function post(); 

    abstract public function put(); 

    abstract public function delete(); 
} 

，我延長CI_Controller_Rest類：

class Welcome extends CI_Controller_Rest { 

    public function __construct() 
    { 
     parent::__construct(); 
    } 

    public function index() {} 

    public function get() {} 

    public function head() {} 

    public function post() {} 

    public function put() {} 

    public function delete() {} 
} 

我應該怎麼做比這更多？

Answer 1

如果一個類有一個或多個抽象功能，it MUST be declared as an abstract class：

abstract class CI_Controller_Rest extends CI_Controller { 

    public function __construct() { 
     parent::__construct(); 
    } 

    abstract public function index(); 

    abstract public function get(); 

    abstract public function head(); 

    abstract public function post(); 

    abstract public function put(); 

    abstract public function delete(); 
} 

Answer 2

abstract class CI_Controller_Rest extends CI_Controller { 
    public function __construct() { 
     parent::__construct(); 
    } 

    abstract public function index(); 

    abstract public function get(); 

    abstract public function head(); 

    abstract public function post(); 

    abstract public function put(); 

    abstract public function delete(); 
} 

Answer 3

，因爲它包含抽象方法

abstract class CI_Controller_Rest extends CI_Controller { 
    public function __construct() { 
     parent::__construct(); 
    } 

    abstract public function index(); 

    abstract public function get(); 

    abstract public function head(); 

    abstract public function post(); 

    abstract public function put(); 

    abstract public function delete(); 
}