设计一个形状类(接口)Shape,方法:求周长和求面积

package co.hp.zy.area;  /**  * 设计形状类(接口)Shape,方法：寻求周长和面积  * 形状类(接口)子类(实现类):  *     Rect(矩形)  *     Circle(圆形)  *  * Rect类的子类:  *     Square(正方形)  *  * 不同的子类会有不同的计算周长和面积的方法  * 创建三个不同的形状对象，放在Shape在类型数组中，每个对象的周长和面积分别打印  */ public interface Shape {     public void perimeter(double bc1,double bc2);     public void acreage(double pi,double bc2); }  

package co.hp.zy.area;  import java.sql.SQLOutput; import java.util.Scanner;  //矩形 public class Rect implements Shape{     @Override     //周长     public void perimeter(double bc1,double bc2) {         //长加宽*2         double peri = (bc1 bc2)*2;         System.out.println("周长为:" peri);     }      @Override     //面积     public void acreage(double bc1,double bc2) {         //长*宽         double acre = bc1*bc2;         System.out.println("面积为:" acre);     } } 

package co.hp.zy.area;  public class Circle implements Shape{      @Override     public void perimeter(double bc1, double bc2) {         //3.14r*r         double peri = bc1*bc2*bc2;         System.out.println("周长为:" peri);     }      @Override     public void acreage(double bc1, double bc2) {         //3.14r*2         double acre = bc1*bc2*2;         System.out.println("面积为:" acre);     } } 

package co.hp.zy.area;  public class Square extends Rect{ } 

package co.hp.zy.area;  import java.util.Scanner;  public class ShapeTest {     public static void main(String[] args) {         Rect r = new Rect();         Circle c = new Circle();         Square s = new Square();         System.out.println("矩形,请输入要计算的矩形边长：");         double bc1 = new Scanner(System.in).nextDouble();         double bc2 = new Scanner(System.in).nextDouble();         r.perimeter(bc1,bc2);         r.acreage(bc1,bc2);          System.out.println("圆,请输入要计算的圆半径：");         double bj = new Scanner(System.in).nextDouble();         double pi = 3.14;         c.perimeter(pi,bj);         c.acreage(pi,bj);          System.out.println("正方形,请输入要计算的正方形边长：");         double zbc1 = new Scanner(System.in).nextDouble();         double zbc2 = zbc1;         s.perimeter(zbc1,zbc2);         s.acreage(zbc1,zbc2);     } } 

运行结果

请输入要计算的矩形边长： 12 10.5 周长为:45.0 面积为:126.0 圆，请输入要计算的圆半径： 2.3 周长为:16.610599999999998 面积为:14.443999999999999 正方形，请输入要计算的正方形边长： 4 周长为:16.0 面积为:16.0