How can the user make their PHP code more robust and expandable to accommodate potential future changes or additions to the temperature monitoring system?

To make the PHP code more robust and expandable for potential future changes or additions to the temperature monitoring system, the user can implement object-oriented programming principles such as encapsulation, inheritance, and polymorphism. By structuring the code into classes and objects, each responsible for specific functionalities, it becomes easier to add new features or modify existing ones without affecting the entire system.

class TemperatureSensor {
    private $location;
    private $temperature;

    public function __construct($location) {
        $this->location = $location;
    }

    public function getTemperature() {
        // Code to retrieve temperature data
        return $this->temperature;
    }

    public function setTemperature($temperature) {
        // Code to set temperature data
        $this->temperature = $temperature;
    }
}

// Example usage
$sensor1 = new TemperatureSensor("Living Room");
$sensor1->setTemperature(25);
echo "Temperature in {$sensor1->getLocation()}: {$sensor1->getTemperature()} degrees Celsius";