Question

<?php

abstract class file
{
    private $pid;
    private $uid;
    public function  __construct($pid,$uid)
    {
        $this->pid = $pid;
        $this->uid = $uid;
    }

    public function valid()
    {
        if($_SESSION['level']<$this->pid)
        {
            return true;
        }
        else
            return false;
    }
    public function allow()
    { 
        return "This is all right!";
    }

}
?>



    <?php
    // put your code here
    include("../file.php");
    session_start();
    class android extends file
    {
        public function __construct($pid,$uid)
        {
            parent::__construct($pid, $uid);

        }
    }

    $uid = $_SESSION['id'];
    $pa = new android(1,$uid);
    if($pa->valid())
            echo $pa->allow();
    else
            echo "<h1>No permission<h1>"

    ?>

The above class is android class and the one above that is file.. Now when the android extends(inherits) the file class, it means it has all the methods. But when I try to run the program, it says undefined variable android::allow()
I dont understand because I have defined the allow() function in the file class and so the android class should inherit the method as well.
please help.. Thanks in advance.

Answer 1

According to http://www.php.net/manual/en/language.oop5.abstract.php ,

Classes defined as abstract may not be instantiated

If your file class doesn’t have any abstract method, don’t bother declaring it as abstract, otherwise avoid calling the constructor 😉