class Switchable a where最后的目标是提供一个函数,期望所有必要的SwitchData并返回树中的叶子。switchOnData [] (Leaf c) = c
switchOnData [] (Node _) = error "switchOnData: partial data
public abstract class Switchable { abstract public void turn_on(); public class Lamp extends Switchable {
publicthis.state=State.off;
System.out.println("lamp's off&
我希望在我的JFrame表单中使用JFrame来交换JPanel --这是JFrame表单的代码: * Creates new form Login initComponents(); * This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The co