public void Undo()
{
if (prevSpeed == CeilingFan.HIGH)
{
_fan.High();
}
else if (prevSpeed == CeilingFan.MEDIUM)
{
_fan.Medium();
}
else if (prevSpeed == CeilingFan.LOW)
{
_fan.Low();
}
else if (prevSpeed == CeilingFan.OFF)
{
_fan.Off();
}
}
public void Execute()
{
prevSpeed = _fan.Speed;
_fan.Low();
}