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); }...

https://www.computersprofessor.com/2016/06/program-for-calculating-area-of.html
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