填空题 读下面程序,写出程序运行结果. class Point{ int x; public Point(){x=0;} public Point(int x){this.x=x;} public void show(){System.out.println(x);}} class SPoint extends Point{ int y; public SPoint(){y=0;} public SPoint(int x,int y){super(x); this.y=y;} public void show(){System.out.println(x+","+y);}} public class tempDemo{ public static void main(String []args){ Point p=new Point(); p.show(); Point p1=new Point(2); p1.show(); SPoint sp=new SPoint(); sp.show(); SPoint sp1=new SPoint(2,3); sp1.show(); }} 运行结果为