$email = "example@email.com"; if (isRegistered($email)) { // allow user to login } else { // show error message }
$email = "example@email.com"; if (isRegistered($email)) { // display registered user content } else { // display non-registered user content }Package/Library: Since "isRegistered" function is not a built-in function in PHP, we can assume that it is a custom function created by a developer for a specific website or application. Therefore, it does not belong to any package or library.