How can short_open_tag settings affect variable assignment in PHP when using require?

Short_open_tag settings can affect variable assignment in PHP when using require because if short tags are enabled, PHP will interpret "<?" as the opening tag instead of "<?php" which may cause issues with variable assignment. To avoid this problem, it is recommended to always use "<?php" for opening tags to ensure compatibility across different server configurations.

<?php
// File: config.php
$database_host = "localhost";
$database_user = "root";
$database_pass = "password";
$database_name = "my_database";
```

```php
<?php
// File: index.php
require 'config.php';

echo "Database Host: " . $database_host;
echo "Database User: " . $database_user;
echo "Database Pass: " . $database_pass;
echo "Database Name: " . $database_name;