S3P2

Describe abstract class called Shape which has three subclasses say Triangle, Rectangle, Circle. Define one method area() in the abstract class and override this area() in these three subclasses to calculate for specific object i.e. area() of Triangle subclass should calculate area of triangle etc. Same for Rectangle and Circle.

 abstract class Shape  
 {  
      int l,b,r;  
      float pi = 3.14f;  
      Shape()  
      {  
           l = 5;  
           b = 10;  
           r = 12;  
      }  
      void area()  
      {  
           System.out.println("\nThis method will be overriden..");  
      }  
 }  
 class triangle extends Shape  
 {  
      void area()  
      {  
           System.out.println("\nArea of Trtingle: "+(l*b)/2);  
      }  
 }  
 class rectangle extends Shape  
 {  
      void area()  
      {  
           System.out.println("\nArea of Rectangle: "+(l*b));  
      }  
 }  
 class circle extends Shape  
 {  
      void area()  
      {  
           System.out.println("\nArea of Circle: "+(pi*r*r));  
      }  
 }  
 class S3P2_abstract_class  
 {  
      public static void main(String args[])  
      {  
           triangle obj1 = new triangle();  
           rectangle obj2 = new rectangle();  
           circle obj3 = new circle();  
           System.out.println("\nl="+obj1.l+", b="+obj1.b+", r="+obj1.r+", pi=3.14");  
           Shape obj;  
           obj = obj1;  
           obj.area();  
           obj = obj2;  
           obj.area();  
           obj = obj3;  
           obj.area();  
      }  
 }  

Output:

   
 E:\Java>javac S3P2_abstract_class.java  
   
 E:\Java>java S3P2_abstract_class  
   
 l=5, b=10, r=12, pi=3.14  
   
 Area of Trtingle: 25  
   
 Area of Rectangle: 50  
   
 Area of Circle: 452.16  
   
 E:\Java>