//  Assume we have a series of x,y coordinates that make up the end points of a polygon.  This program computes the polygon's total distance around (its perimeter).  We use the Euclidean distance
//  formula to compute the distance between any two points x1,y1 and x2,y2 (Math.sqrt((x1-x2)^2+(y1-y2)^2).  We store all of the x,y coordinates in two arrays.  We assume int coordinates but 
//  distance is computed as a double

public class ComputePerimeter
{
	public static void main(String[] args)
	{
		int[][] points = {{1,1},{5,3},{8,2},{6,9},{8,3},{4,2},{3,4}};
		int n = 7;			// 7 points
		double sum = 0.0;
		for(int i=0;i<n;i++)		
			sum+=distance(points, i, n);
		System.out.printf("This polygon of %d points has a perimeter of %7.2f", n, sum);
	}
	
	public static double distance(int[][] p, int i, int n)			// when i==n-1, we are on the last point, use point 0 as the other point
	{
		int x1 = p[i][0], y1 = p[i][1];
		int x2, y2;
		if(i==n-1) {
			x2 = p[0][0];
			y2 = p[0][1];
		}
		else {
			x2 = p[i+1][0];
			y2 = p[i+1][1];
		}
		return Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));
	}
}