interface Shape {
    // all methods abstract by default
    public double Area();
        
    static double Pi = 3.14159;
}

class Circle implements Shape {
    int radius;

    Circle(int r) {
	this.radius = r;
    }

    public double Area() {
	return Pi * radius * radius;
    }
}

abstract class Quadrilateral implements Shape {
    // Any classes that extend Quadrilateral should have a Perimeter
    // method.

    abstract int Perimeter();

    // concrete method
    public String toString() {
	String str = "I am a Quadrilateral of perimeter "+ 
	    this.Perimeter() + ", calling Object's toString " + 
	    super.toString();
	return str;
    }
}

class Rectangle extends Quadrilateral {
    Rectangle(int w, int h) {
	this.width = w;
	this.height = h;
    }
    
    // Yields a rectangle with aspect ratio 2:1
    Rectangle(int h) {
	//	height = h;
	//	width = 2*h;

	this(2*h, h);
    }


    public String toString() {
	String str1 = "I am a rectangle of width "
	    + width + " and height " + height +
	    ". My area is " + Area() + ";" + super.toString();
	
	return str1;
    }

    public double Area() {
	return (width*height);
    }

    public int getWidth() {
	//	int foo;
	//	foo=foo+1; // not initialized

	return width;
    }

    public int Perimeter() {
	return (2 * width + 2 * height);
    }
    
    private int width;
    private int height;
    //    public static final double pi = 3.14;
}

class Square extends Rectangle {
    Square(int side) {
	//	width = side;
	//	height = side;
	super(side,side);
    }

    public String toString() {
	return "I am a square!!!" + super.toString();
    }
}


public class OOPDemo2 {
    public static void main(String args[]) {
	Rectangle rec1 = new Rectangle(new Integer(10),4);
	Rectangle rec2 = new Rectangle(5,6);
	Rectangle rec3 = new Rectangle(8);

	System.out.println(rec1);
	System.out.println(rec2);
	//	rec1.Area();
	System.out.println(rec1.getWidth());

	System.out.println(rec3);
	
	Square sqr1 = new Square(15);

	System.out.println(sqr1);
	
	Circle cir1 = new Circle(3);
	System.out.println("The area of cir1 is " + cir1.Area());
    }
}