import java.util.*;

public class ShapeTest {
	public static void main(String[] args) {
		Shape r = new Rectangle(10, 13);
		System.out.println(r.area());
		
		Shape c = new Circle(20);
		System.out.println(c.area());
		
		List<Shape> shapes = new LinkedList<Shape>();
		shapes.add(c);
		shapes.add(r);
		
		for(Shape s : shapes) {
			System.out.println(s.area());
			System.out.println(s);
		}
	}
}