Inheritance in PHP
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Inheritance in PHP
Inheritance is one of the most important aspects of OOP. It allows a class to inherit members from another class. When a class is defined by inheriting existing function of a parent class then it is called Inheritance. Here child class will inherit all or few member functions and variables of a parent class.
For inherit one class into another class use extends keyword. In any language inheritance is used for reuse all ready written code in project.
Syntax
<?php
class A
{
// more code here
}
class B extends A
{
// more code here
}
class C extends B
{
// more code here
}
$obj1 = new A(); // no problems
$obj2 = new B(); // no problems
$obj3 = new C(); // still no problems
?>
Example of Inheritance in PHP
<?php
class Foo
{
public function printItem($string)
{
echo 'Foo: ' . $string . PHP_EOL;
}
public function printPHP()
{
echo 'PHP is great.' . PHP_EOL;
}
}
class Bar extends Foo
{
public function printItem($string)
{
echo 'Bar: ' . $string . PHP_EOL;
}
}
$foo = new Foo();
$bar = new Bar();
$foo->printItem('baz'); // Output: 'Foo: baz'
$foo->printPHP(); // Output: 'PHP is great'
$bar->printItem('baz'); // Output: 'Bar: baz'
$bar->printPHP(); // Output: 'PHP is great'
?>
Output
Foo: baz PHP is great. Bar: baz PHP is great.
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