// CS 1538 Fall 2009
// Simple demonstration of Monte Carlo simulation to determine the area
// of a circle.  Looking at it another way, we could also use this
// simulation to estimate the value of pi (since a unit circle is used).

import java.util.*;
public class Circle
{
	public static void main(String [] args)
	{
		int iter = Integer.parseInt(args[0]);
		Random r = new Random();
		int hits = 0;
		for (int i = 0; i < iter; i++)
		{
			double rX = 2*r.nextDouble() - 1.0; // Gen. random x
			double rY = 2*r.nextDouble() - 1.0; // Gen. random y
			double dist = Math.sqrt(rX*rX + rY*rY);  // Get distance
			if (dist <= 1.0)	// If distance is <= 1 from the origin
				hits++;			// the point is within the circle
		}
		double ratio = (double)hits/iter; // Ratio of areas
		System.out.println("The ratio is " + ratio);
		double area = ratio * 4.0;  // We know the area of the square is 4.0
		System.out.println("The area is " + area);
	}
}