using System;

namespace april12
{
	public class Point 
	{
		private double x;
		private double y;

		public Point(double x, double y) 
		{
			this.x = x;
			this.y = y;
		}

		public double X
		{
			get { return x; }
		}

		public double Y
		{
			get { return y; }
		}
	}

	public abstract class Shape
	{
		private Point location;

		public Shape(Point p)
		{
			location = p;
		}

		public Point Location
		{
			get { return location; }
		}

		public abstract double Area();
	}

	public class Circle : Shape
	{
		private double radius;

		public Circle(Point center, double r) : base(center)
		{
			radius = r;
		}

		public override double Area()
		{
			return Math.PI * Math.Pow(radius, 2.0);
		}
	}

	public class Rect : Shape
	{
		private Point toPoint;

		public Rect(Point from, Point to) : base(from)
		{
			toPoint = to;
		}

		public override double Area()
		{
			double width;
			double height;

			width = Math.Abs(toPoint.X - Location.X);			
			height = Math.Abs(toPoint.Y - Location.Y);

			return width * height;
		}
	}

	public class TestShape
	{
		public static void Main()
		{
			Point center = new Point(3.0, 3.0);
			double radius = 2.0;

			Circle c = new Circle(center, radius);
			Console.WriteLine("Circle area: {0:F6}",c.Area());

			Point from, to;
			from = new Point(1.0, 3.0);
			to = new Point(-3.0, 8.0);
			Rect r = new Rect(from, to);
			Console.WriteLine("Rect area: " + r.Area());			
		}
	}
}