How to create default function parameter in PHP?

The default parameter concept comes from C++ style default argument values, same as in PHP you can provide default parameters so that when a parameter is not passed to the function. Then it is still available within the function with a pre-defined value. This function also can be called optional parameter. 

Syntax:

function greeting($name=" parameter_value ")

Parameter: This function accepts a single parameter that is $name here, holds the parameter value. 

Below examples illustrate the procedure to create and use the default function parameter.

Example 1: 

<?php  
    function greeting($name="GeeksforGeeks")
    {  
        echo "Welcome to $name ";  
        echo("\n");
    }  
    greeting("Gfg"); 

    // Passing no value 
    greeting(); 
    greeting("A Computer Science Portal");  
?>  

Output:

Welcome to Gfg 
Welcome to GeeksforGeeks 
Welcome to A Computer Science Portal 

Example 2: 

<?php    
    function welcome($first="GeeksforGeeks",
                     $last="A Computer Science Portal for Geeks")
                     {    
                        echo "Greeting: $first $last";   
                        echo("\n");
    }    
    welcome();  
    welcome("night_fury");  
    welcome("night_fury","Contributor");  
?>    

Output:

Greeting: GeeksforGeeks A Computer Science Portal for Geeks
Greeting: night_fury A Computer Science Portal for Geeks
Greeting: night_fury Contributor