package zhongqiuzuoye;public interface ShapePara {public  double getArea();public  double getCircumference();}

package zhongqiuzuoye;public class Circle implements ShapePara {public double radius;private double x;public double getRadius() {return radius;}public void setRadius(double radius) {this.radius = radius;}public double getX() {return x;}public void setX(double x) {this.x = x;}public double getY() {return y;}public void setY(double y) {this.y = y;}protected double y;public   Circle(double radius) {}void setCenter(double x, double y){this.x=x;this.y=y;}public double getArea() {return 3.14*radius*radius;}@Overridepublic double getCircumference() {// TODO 自动生成的方法存根return 0;}}

package zhongqiuzuoye;public class Shape {public void getArea(){}
}

package zhongqiuzuoye;public class Rect extends Shape{private double width;private double height;public double getWidth() {return width;}public void setWidth(double width) {this.width = width;}public double getHeight() {return height;}public void setHeight(double height) {this.height = height;}Rect(double width,double height)         //带有两个参数的构造方法,用于将width和height属性初化;
    {this.width=width;this.height=height;}public void getArea()                    //求矩形面积的方法
    {System.out.println("矩形的面积为："+width*height);}}

package zhongqiuzuoye;public interface A {public static void main(String args[]) {    Rect rect=new Rect(12.76, 25.28);                System.out.println("矩形对象的宽："+rect.getWidth()+" 高："+rect.getHeight()+"面积为:");    rect.getArea();}
}