继承求不同形状图形的周长和面积
package LESSON6; //形状类 class Shape{ public final double PI=3.14; public double s;//面积 public double c;//周长 public Shape(double l,double h){ this.s=l*h; this.c=2*(l+h); System.out.println("矩形面积:"+s+"周长:"+c); } public Shape(double r){ this.s=PI*r*r; this.c=2*PI*r; System.out.println("圆面积:"+s+"周长:"+c); } } //矩形类 class Rect extends Shape{ public Rect(double h){ super(1.0,1.2);//矩形 this.s=h*h; this.c=4*h; System.out.println("正方形"+"面积:"+s+"周长:"+c); } } //圆形类 class Circle extends Shape{ public Circle(){ super(3);//矩形 } } //正方形类 class Square extends Rect{ public Square(){ super(4); } } public class Exercise { public static void main(String[] args) { Rect re=new Rect(2); Circle cir=new Circle(); // Square sq=new Square();//正方形对象不需创建,在创建矩形对象时已经输出的正方形的周长和面积 } }