headphone_override_2.dart

class Headphone {
  double volume = 5;
  double volumeUnit = 1;

  void increaseVolume() {
    if (volume == 10) {
      print('최고 볼륨입니다!');
      return;
    }

    volume += volumeUnit;
  }

  void decreaseVolume() {
    if (volume == 0) {
      print('최저 볼륨입니다!');
      return;
    }

    volume -= volumeUnit;
  }
}

class BluetoothHeadphone extends Headphone {
  bool isPlaying = false;

  @override
  double get volumeUnit => 0.5;

  void togglePlay() {
    isPlaying = !isPlaying;
  }
}

void main() {
  BluetoothHeadphone bluetoothHeadphone = BluetoothHeadphone();
  bluetoothHeadphone.increaseVolume();
  print(bluetoothHeadphone.volume); // 5.5
}