explain function defining and calling a function in PHP

A function is a piece of code which takes one more input in the form of a parameter and does some processing and returns a value.

There are two parts which should be clear to you −

• Creating a PHP Function
• Calling a PHP Function

It’s very easy to create your own PHP function. Suppose you want to create a PHP function which will simply write a simple message on your browser when you call it. Following example creates a function called writeMessage() and then calls it just after creating it. Note that while creating a function its name should start with keyword function and all the PHP code should be put inside { and } braces as shown in the following example below −

      <?php

         /* Defining a PHP Function */

         function writeMessage() {

            echo “You are really a nice person, Have a nice time!”;

         }

         /* Calling a PHP Function */

         writeMessage();

      ?>

Result −

You are really a nice person, Have a nice time!

PHP Functions with Parameters

PHP gives you the option to pass your parameters inside a function. You can pass as many parameters as you like. These parameters work like variables inside your function. 

  <?php

         function addFunction($num1, $num2) {

            $sum = $num1 + $num2;

            echo “Sum of the two numbers is : $sum”;

         }       

         addFunction(10, 20);

      ?>  

Result −

Sum of the two numbers is : 30