php - 错误：必须将类声明为抽象类或实现其余方法

Question

我有一个实现几个抽象方法的类。当我扩展该类时，我收到以下致命错误消息：

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

具有抽象方法的类：

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();
}  

我扩展的类CI_Controller_Rest：

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() {}
}  

除了这些，我还应该做什么？

Answer 1

如果一个类有一个或多个抽象函数，它必须被声明为一个抽象类：

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

CI_Controller_Rest 必须是抽象类，因为它包含抽象方法

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();
}