public string Undo() { if (_prevSpeed.Equals(Fan.High)) { _fan.SetHigh(); } if (_prevSpeed.Equals(Fan.Medium)) { _fan.SetMedium(); } if (_prevSpeed.Equals(Fan.Low)) { _fan.SetLow(); } if (_prevSpeed.Equals(Fan.Off)) { _fan.SetOff(); } return("fan set speed error"); }
public string Execute() { _prevSpeed = _fan.Speed; return(_fan.SetOff()); }