I'm getting to grips with Object Oriented PHP, but there's something I really don't understand about inheritance.

See this script:

PHP Code:

<?php

/**
 * Define MyClass
 */
class MyClass
{
    public $public = 'Public';
    protected $protected = 'Protected';
    private $private = 'Private';
}

$obj = new MyClass;
echo $obj->public;

?>

I can access the public property fine, but when I try to echo 'protected' or 'private', I just see a blank screen!

I thought they would all be accessible from this object? I thought protected wouldn't be accessible from an object that wasn't of 'MyClass' (or any of its parents / children) and that private would only be accessible from an object of MyClass.

I'm guessing I have the wrong idea?

Also, I very rarely see any error messages with and OOP scripts! I have both XAMPP and MAMP installed on my Mac, but I mostly just see a blank screen when something goes wrong.

Do I need to change the error settings for my PHP installation or is this normal behaviour?

You cannot access private or protected member variables or methods from outside of a class. Protected variables can be accessed from a parent or child class, as well as the class itself. Private variables can only be accessed from the class itself. You should be seeing an error message like this:

Fatal error: Cannot access private property MyClass::$private

Make sure error reporting is enabled in your php.ini

The code you posted doesn't really have anything to do with inheritance. Here is an example of inheritance:

PHP Code:

class MyClass
{
    public $a = 'Public';
    protected $b = 'Protected';
    private $c = 'Private';
}

class MyChildClass extends MyClass
{
     function foo()
     {
          echo $this->b;
     }
}

$obj = new MyChildClass;
echo $obj->a;
$obj->foo(); 


a can be accessed from outside of either class. b can be accessed from within either class. c can only be accessed within MyClass.

Ohhhh yeah I meant to say 'Visibility', haha, Im sure you can tell I'm new to this.

Thanks.