import java.util.*;			// for Comparator and Random

public class Ch22_4			// this program will create a Point class and then implement two different ways to
{							// compare Points for sorting, using compareTo in the Point class and a separate
	public static void main(String[] args)			// class that implements Comparator which will be used by sort
	{
		Random g=new Random();				
		Point[] points=new Point[100];		// we will create 100 random points
		for(int i=0;i<100;i++)
			points[i]=new Point(g.nextInt(100),g.nextInt(100));
		Arrays.sort(points);				// sort the array using Point's compareTo, which sorts x-coordinates and
		for(int i=0;i<100;i++)						// if equal, uses the y-coordinates to break the tie
			System.out.println(points[i]);	// print them out
		System.out.println("\n\n");
		Arrays.sort(points,new CompareY());	// now sort the array using CompareY as Comparator, this class sorts
		for(int i=0;i<100;i++)						// on y-coordinates first and then x-coordinates in a tie
			System.out.println(points[i]);	// print them out
	}
	
	private static class Point implements Comparable		// our Point class contains a compareTo method
	{
		private int x, y;
		
		public Point(int x, int y)
		{
			this.x=x;
			this.y=y;
		}

		public int getX() {return x;}		
		public int getY() {return y;}		
			
		public int compareTo(Object o)		// because we did not implement Comparable<Point> we receive an Object
		{				
			Point p=(Point)o;				// so we have to cast o as a Point to pass it messages
			if(x!=p.getX()) return x-p.getX();	// if x's are not the same, return their difference
			else return y-p.getY();				// and if x's are the same, return the difference in y's
		}
		
		public String toString()
		{
			return x+","+y;		// so we can output it in main easily using println
		}
	}
	
	private static class CompareY implements Comparator<Point>	// here we implement a separate means to compare two
	{															// Points so that we can see how a Comparator is used
		public boolean equals(Point p1)							// with Arrays.sort
		{
			return false;			// note: since CompareY does not store a Point, there is nothing to compare p1 to
		}							// so it returns false, this is a useless method but needed to implement
									// Comparator
		public int compare(Point p1, Point p2)		// since we are implementing Comparator<Point> no casting needed
		{
			if(p1.getY()!=p2.getY()) return p1.getY()-p2.getY();	// use the same strategy for comparing two Points
			else return p1.getX()-p2.getX();						// as compareTo except compare y's first
		}
	}
}