What is the significance of using sessions to maintain login status in a PHP application?

Using sessions to maintain login status in a PHP application is significant because it allows the server to keep track of the user's authentication status across multiple requests. This ensures that only authenticated users can access certain parts of the application, providing security and privacy for sensitive information. Sessions also make it easier to manage user data and customize the user experience based on their login status.

// Start the session
session_start();

// Check if the user is logged in
if(isset($_SESSION['user_id'])) {
    // User is logged in, perform necessary actions
} else {
    // User is not logged in, redirect to login page
    header("Location: login.php");
    exit();
}