Solution: Smart Greenhouse Monitor

void main() {
  final dailyTemperatures = [12, 22, 18, 35, 14, 28];
  
  for (final temp in dailyTemperatures) {
    if (temp < 15) {
      print('Heater activated.');
    } else if (temp > 30) {
      print('Cooler activated.');
    } else {
      print('Optimal.');
    }
  }
}