What are best practices for structuring PHP code when processing form submissions?

When processing form submissions in PHP, it is best practice to separate your code into different files or functions to improve readability and maintainability. One common approach is to have a separate file for form validation, another for processing the form data, and a third for displaying the results. This helps to keep your code organized and makes it easier to debug and update in the future.

// form_validation.php
function validateForm($formData) {
    // Add your form validation logic here
    // Return true if validation passes, false otherwise
}

// process_form.php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if (validateForm($_POST)) {
        // Process the form data and perform necessary actions
    } else {
        // Handle validation errors
    }
}

// display_results.php
// Display the results of the form submission