In this tutorial, you shall learn about Inheritance in PHP, an Object Oriented Programming concept, how it can be implemented in PHP programs, with examples.

Inheritance

Inheritance is a way in which a new class (child class or subclass) can be created to inherit all the properties and methods of the existing class (parent class or superclass).

To implement inheritance in PHP, we can use extends keyword.

Example

In the following example, we create two classes: ParentClass and ChildClass. As the name suggests, ChildClass extends/inherits ParentClass, and therefore extends the properties and methods of the ParentClass.

PHP Program

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<?php
class ParentClass {
   // properties and methods
}

class ChildClass extends ParentClass {
   // properties and methods
}
?>

Now, let us define some properties and methods for the ParentClass. Then we create a new object $child1 of type ChildClass, and access the property $x and function sayHello() of the ParentClass using ChildClass object $child1.

PHP Program

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<?php
class ParentClass {
  public $x = 10;
  public function sayHello() {
    print_r("Hello from Parent class.\n");
  }
}

class ChildClass extends ParentClass {

}

$child1 = new ChildClass();
$child1->sayHello();
print_r($child1->x);
?>

Output