class Point{ protected int x,y; public Point(){} public Poin

class Point{ protected int x,y; public Point(){} public Point(int xx,int yy){setPoint(xx,yy);}
public void setPoint(int m,int n){x=m;y=n;}
public int getX(){return x;}
public int getY(){return y;}}
class Circle extends point{
private double radius;
public Circle(int x,int y,double r){this.x=x;this.y=y;steRadius(r);}
public void setRadius(double r){radius=r;}
public double getRadius(){retuen radius;}
public double getArea(){retuen 3.1415*radius*radius;}
public String toString()
{
retuen "Poistion("+x+","+y+")Radius="radius;}}
public class CircleTest
{
public static void main(String args[]){
Circle c=new Circle(50,50,10);
System.out.prinrln(c.toString());
c.setPoint(100,100);
c.setRadius(20);
System.out.println(c.toString());
}}
1：父类的public Point(){}构造方法为什么不能省略,它是初始化谁的?
2:父类的public Point(int xx,int yy){setPoint(xx,yy);}构造方法是初始化谁的?为什么形参是（xx,yy)而不是(g,h)?