class Circunferencia
{
	double radio;
	
	public Circunferencia(double r)
	{
		this.radio = r;	
	}	
	
	public Circunferencia()
	{
		this(1);	
	}
	
	public double area()
	{
		return 2 * Math.PI * radio;	
		
	}
	
	public double perimetro()
	{
		return Math.PI * Math.pow(radio,2);	
	}
	

	public static void main(String arg[])
	{
		Circunferencia c = new Circunferencia();
		
		System.out.println(" c : circunferencia de radio 1 ");
		System.out.println(" area : " + c.area());
		System.out.println(" perimetro : " + c.perimetro());	

		System.out.println("\n");

		/* nueva circunferencia de radio PI */		
		
		c = new Circunferencia(Math.PI);

		System.out.println(" c : circunferencia de radio PI");
		System.out.println(" area : " + c.area());
		System.out.println(" perimetro : " + c.perimetro());

		System.out.println("\n");
	}
}