How can the use of PHP constants, like in the maincome.php file, impact file inclusion and path resolution?

Using PHP constants in file paths can make the code more maintainable and easier to update since you only need to change the constant value in one place. It also helps in avoiding hardcoding file paths, making the code more flexible and reusable. Additionally, constants can be defined once and used multiple times throughout the application, ensuring consistency in file inclusion and path resolution.

// Define a constant for the base directory
define('BASE_DIR', __DIR__);

// Include a file using the constant for the base directory
include BASE_DIR . '/path/to/file.php';