1 abstract class Shape { 2 public abstract float area(); 3 public abstract void printArea(); 4 } 5 class Rectangle extends Shape { 6 int width; 7 int length; 8 public Rectangle(int newWidth,int newLength) { 9 width=newWidth; 10 length=newLength; 11 } 12 public float area() { 13 float area=width*length; 14 return area; 15 } 16 public void printArea() { 17 System.out.println("矩形的面積: "+area()); 18 } 19 } 20 class Circle extends Shape { 21 final float PI=3.14F; 22 int radius; 23 public Circle(int newRadius) { 24 radius=newRadius; 25 } 26 public float area() { 27 float area=PI*radius*radius; 28 return area; 29 } 30 public void printArea() { 31 System.out.println("圓的面積: "+area()); 32 } 33 } 34 class ChouXiang { 35 public static void main(String[] args) { 36 Rectangle s1=new Rectangle(3,4); 37 Circle s2=new Circle(2); 38 s1.printArea(); 39 s2.printArea(); 40 } 41 }
有什麼意見,下面評論區說哈。