抽象类（面积计算问题）

来源：互联网发布：nvm windows 淘宝镜像编辑：程序博客网时间：2024/04/30 05:56

package programT5_3;/** * 编写一个抽象类Shape，声明计算图形面积的抽象方法。 * 再分别定义Shape的子类Circle（圆）和Rectangle（矩形）， * 在两个子类中按照不同图形的面积计算公式，实现Shape类中计算面积的方法。 * @author Administrator * */public abstract class Shape {     abstract void area1();}

package programT5_3;public class Circle extends Shape {    private double r;    private double area;    public double getArea() {        return area;    }    public void setArea(double area) {        this.area = area;    }    public double getR() {        return r;    }    public void setR(double r) {        this.r = r;    }    @Override    public void area1() {        area=3.14*r*r;        System.out.println("半径为"+r+"的圆面积为："+String.format("%.2f", area));    }}

package programT5_3;public class Rectangle extends Shape {    private double a;    private double b;    private double area;    public double getA() {        return a;    }    public void setA(double a) {        this.a = a;    }    public double getB() {        return b;    }    public void setB(double b) {        this.b = b;    }    public double getArea() {        return area;    }    public void setArea(double area) {        this.area = area;    }    @Override    public void area1() {        area=a*b;        System.out.println("边长为："+a+"和"+b+"的矩形面积为："+String.format("%.2f", area));    }}

package programT5_3;public class TestArea {    public static void main(String[] args) {        Circle c=new Circle();        Rectangle rect=new Rectangle();        c.setR(3.89);        rect.setA(3.56);        rect.setB(8.35);        c.area1();        rect.area1();    }}

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