package ӿںͳ;

public class Example6_7 {
	public static void main(String args[]) {
		ColorCircle cir;
		cir = new ColorCircle(2.0);
		cir.setColor("blue");
		System.out.println("Area = " + cir.area());
	}
}

abstract class Shape2D {
	final double pi = 3.14;

	public abstract double area();
}

interface Color {
	void setColor(String str);
}

class ColorCircle extends Shape2D implements Color {
	double radius;

	String color;

	public ColorCircle(double r) {
		radius = r;
	}

	public double area() {
		return (pi * radius * radius);
	}

	public void setColor(String str) {
		color = str;
		System.out.println("color=" + color);
	}
}