一道java编程题目！

public class AreaTest{
public static void main(String args[]){
RoundArea round=new RoundArea();
round.r=1.256;
System.out.println("圆1半径为: "+String.valueOf(round.r));
System.out.println("圆1面积为: "+round.area());

System.out.println();
RectArea rect=new RectArea();
rect.width=1.25;
rect.height=2.56;
System.out.println("矩形1宽: "+String.valueOf(rect.width));
System.out.println("矩形1高: "+String.valueOf(rect.height));
System.out.println("矩形1面积: "+rect.area());
}
}

abstract class Area {
abstract double area();
}
class RoundArea extends Area {
double r;
double area() {
return 3.14159*r*r;
}
}
class RectArea extends Area {
double width;
double height;
double area() {
return width*height;
}
}