package javaDemo;

public class TestDemo {
    public static void main(String []args){
       System.out.println("Square's area:\t"+(new Square()).area(2));
       System.out.println("Circle's area:\t"+(new Circle()).area(3));
    }
}
interface Shape{
    abstract double area(double one);
}
class Square implements Shape{
    public double area(double one){
        return one*one;
    }
}
class Circle implements Shape{
    public  double area(double two){
        return Math.PI*Math.pow(two,2);
    }
}