就能在不發生錯誤的情況下執行。本課程的下一部分將介紹 如何從這些結構中取得資料。 /// An event in the elevator system that the controller must react to. enum Event { // TODO: add required variants } /// A direction of travel. enum Direction { }", car_arrived(3)); } 10.6.1 解決方案 /// An event in the elevator system that the controller must react to. enum Event { /// A button was pressed. ButtonPressed(Button), /// The car has arrived at the