Abstract classes in PHP

Related Links

• http://php.net/manual/en/language.oop5.interfaces.php
• http://www.techflirt.com/tutorials/oop-in-php/abstract-classes-interface.html

What is class abstraction?

• PHP 5 introduces abstract classes and methods.
• Usually abstract class are also known as base class.
• Abstract classes are those classes which can not be directly initialized. Or in other word we can say that you can not create object of abstract classes.
• Any class that contains at least one abstract method must also be abstract.
• Abstract classes always created for inheritance purpose. You can only inherit abstract class in your child class.
• It can only act as parent class of any normal class. You can use abstract class in class hierarchy. Mean one abstract class can inherit another abstract class also.
• A protected abstract function can be implemented as either protected or public but not private.