Basic PHP tutorial

Advanced PHP tutorial

The class_exists() function checks if the class is defined

class_exists　(　$class_name　[,$autoload]　);

This function checks if the given class is defined. If class_name is a defined class, it returns TRUE, otherwise it returns FALSE.

Serial number	Parameters and descriptions
1	class_name(Required) Class name.
2	autoload(Optional) Whether to call __autoload by default.

If class_name is a defined class, it returns TRUE, otherwise it returns FALSE.

The following is the usage of this function, to check if the class HelloWorld is defined-

<?php
　　　if　(class_exists('HelloWorld'))　{
　　　　　　$helloworld　=　new　HelloWorld();
　　　}
?>