Function Overloading in PHP
Function overloading is a feature that permits making creating several methods with a similar name that works differently from one another in the type of the input parameters it accepts as arguments.
Example
Let us now see an example to implement function overloading−
Live Demo
<?php class Shape { const PI = 3.142 ; function __call($name,$arg){ if($name == 'area') switch(count($arg)){ case 0 : return 0 ; case 1 : return self::PI * $arg[0] ; case 2 : return $arg[0] * $arg[1]; } } } $circle = new Shape(); echo $circle->area(3); $rect = new Shape(); echo $rect->area(8,6); ?>Output
This will produce the following output−
9.42648Function Overriding in PHP
In function overriding, the parent and child classes have the same function name with and number of arguments
Example
Let us now see an example to implement function overriding−
Live Demo
<?php class Base { function display() { echo "\nBase class function declared final!"; } function demo() { echo "\nBase class function!"; } } class Derived extends Base { function demo() { echo "\nDerived class function!"; } } $ob = new Base; $ob->demo(); $ob->display(); $ob2 = new Derived; $ob2->demo(); $ob2->display(); ?>Output
This will produce the following output−
Base class function! Base class function declared final! Derived class function! Base class function declared final!
Updated on 02-Jan-2020 06:36:33
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Method Overloading is a concept of Object Oriented Programming which helps in building the composite application in an easy way. Function overloading or method overloading is a feature that permits making creating several methods with a similar name that works differently from one another in the type of the input parameters it accepts as arguments.
The above concept is fine for other programming languages and it is called static polymorphic i.e method overloading.
Example
Let's understand through an example.
<?php class machine { function doTask($var1){ return $var1; } function doTask($var1,$var2){ return $var1 * $var1 ; } } $task1 = new machine(); $task1->doTask(5,10); ?>Output:
ErrorExplanation:
This will generate an error since php will say you have declared this method twice.
But Other programming languages says , doTask($var1) and doTask($var1,$var2) are overloaded methods. To call the latter, two parameters must be passed, whereas the former requires only one parameter.
so this behavior i.e decision to call a function at coding time is known as static polymorphic i.e method
overloading.
Let's discuss how to achieve method overloading related to PHP5.In the case of PHP, we have to utilize PHP's magic methods __call() to achieve method overloading.
In PHP overloading means the behavior of method changes dynamically according to the input parameter. In this tutorial, we will understand those perceptions. Let's discuss the __call() method.
__call():
If a class execute __call(), then if an object of that class is called with a method that doesn't exist then__call() is called instead of that method.
Example
Let's understand method overloading with an example.
<?php class Shape { const PI = 3.142 ; function __call($name,$arg){ if($name == 'area') switch(count($arg)){ case 0 : return 0 ; case 1 : return self::PI * $arg[0] ; case 2 : return $arg[0] * $arg[1]; } } } $circle = new Shape(); echo $circle->area(3); $rect = new Shape(); echo $rect->area(8,6); ?>Output:
9.426 48Explanation:
Here area() method is created dynmically and executed with the help of magic method __call() and it's behaviour changes according to pass of parametrs as object.
Updated on 31-Dec-2019 08:29:38
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