PHP | ReflectionParameter getDefaultValueConstantName() Function

The ReflectionParameter::getDefaultValueConstantName() function is an inbuilt function in PHP which is used to return the default value's constant name if default value is constant or null. Syntax:

 string ReflectionParameter::getDefaultValueConstantName ( void )

Parameters: This function does not accept any parameters. Return Value: This function returns the default value's constant name if default value is constant or null. Below programs illustrate the ReflectionParameter::getDefaultValueConstantName() function in PHP: Program 1:

php

<?php
 
// Initializing a user-defined class Company1
class Company1
{
    function GFG($Full_Name = GeeksforGeeks){}
}
  
// Initializing a subclass Company2
class Company2 extends Company1
{
}
  
// Using the ReflectionParameter over the above class
$A = new ReflectionParameter(['Company2', 'GFG'], 0); 
  
// Calling the getDefaultValueConstantName() function
$B = $A->getDefaultValueConstantName();
  
// Getting the default value's constant name 
// if default value is constant or null
var_dump($B);
?>

Output:

string(13) "GeeksforGeeks"

Program 2:

php

<?php
  
// Initializing some user-defined classes
class Department1
{
    function HR( $Full_Name = Human_Resource){}
}
class Department2
{
    function Coding( $Parameter2, $Par3 = Parameter3){}
}
class Department3
{
    function Marketing( $Parameter4 = Digital_Marketing, $Parameter5){}
}
  
// Using the ReflectionParameter over the above classes
$A = new ReflectionParameter(['Department1', 'HR'], 0);
$B = new ReflectionParameter(['Department2', 'Coding'], 1);
$C = new ReflectionParameter(['Department3', 'Marketing'], 0);
  
// Calling the getDefaultValueConstantName() function and 
// getting the default value's constant name if 
// default value is constant or null
var_dump($A->getDefaultValueConstantName());
var_dump($B->getDefaultValueConstantName());
var_dump($C->getDefaultValueConstantName());
?>

Output:

string(14) "Human_Resource"
string(10) "Parameter3"
string(17) "Digital_Marketing"

Reference: https://www.php.net/manual/en/reflectionparameter.getdefaultvalueconstantname.php