PHP | class_exists() Function

The class_exists() function is an inbuilt function in PHP which is used to check whether the given class is defined or not. Syntax:

bool class_exists( string $class_name, bool $autoload = TRUE )

Parameters: This function accept two parameters as mentioned above and described below:

• $class_name: It holds the class name which need to check their existence.
• $autoload: It checks whether the __autoload is called or not by default.

Return Value: This function returns True if class name is defined otherwise returns False. Below programs illustrate the class_exists() function in PHP: Program 1: php

<?php

// Create a class
class GFG {
    public $Geek_name = "Welcome to GeeksforGeeks"; 
} 

// Check class name exist or not
if(class_exists('GFG')) {
    echo "Class name exists";
}
else {
    echo "Class name does not exist";
}

?>

Program 2: php

<?php

// Creating class 
class GFG { 
    public $data1; 
    public $data2; 
    public $data3; 
}

if(class_exists('GFG')) {

    // Creating an object 
    $obj = new GFG();

    // Set values of $obj object 
    $obj->data1 = "Geeks"; 
    $obj->data2 = "for"; 
    $obj->data3 = "Geeks"; 

    // Print values of $obj object 
    echo "$obj->data1  \n$obj->data2  \n$obj->data3"; 
}
else {
    echo "Class does not exist";
}

?>

Reference: https://www.php.net/manual/en/function.class-exists.php