写出程序结果: class Fu { int num = 4; void show() { System.out.println("Fu show"); } } class Zi extends Fu { int num = 5; void show() { System.out.println("Zi show"); } } public class Demo { public static void main(String[] args) { Fu f = new Zi(); Zi z = new Zi(); System.out.println(f.num); System.out.println(z.num); f.show(); z.show(); } }