PROGRAM FOR CALCULATING AREA OF A RECTANGLE AND CIRCLE USING INTERFACES

import java.lang.*;

interface Area

{

              final static float pi=3.14F;

              float compute (float x,float y);

}

class Rectangle implements Area

{

             public float compute(float x,float y)

            {

                         return x*y;

            }

}

class Circle implements Area

{

            public float compute(float x,float y)

            {

                         return(pi*x*x);

           }

}  

class InterfaceTest

{

  public static void main(String args[])

   {

            Rectangle rect=new Rectangle();

            Circle cir=new Circle();

            Area area;

            area=rect;

            System.out.println("Area of Rectangle="  +area.compute(10,20));

            area=cir;

            System.out.println("Area of Circle="  +area.compute(10,20));

    }

}

OUTPUT:

Area of Rectangle=200.0

Area of Circle=314.0