public class ComparableCircles implements Comparable		// example of a Circle that implements Comparable
{
	private int x, y, r;		// center (x,y) and radius
	
	public ComparableCircles()	// no arg constructor, initialize all to 0
	{
		x=y=r=0;
	}
	public ComparableCircles(int x, int y, int r)		// normal constructor
	{
		this.x=x;
		this.y=y;
		this.r=r;
	}
	
	//accessors
	public int getX() {return x;}
	public int getY() {return y;}
	public int getRadius() {return r;}
	
	// toString describes the circle
	public String toString()
	{
		return "This circle has a center point at " + x + "," + y + " and has a radius of " + r;
	}
	
	// implement Comparable here
	@Override
	public int compareTo(Object o)		// receive an Object and put it in a variable of type ComparableCircles so that we don't have
	{									// to do further casting
		ComparableCircles other=(ComparableCircles)o;
		return r-other.getRadius();		// compareTo just compares radii, if this Circle's r > other's r, return +number, if < return -number, 
	}									//    returns 0 if the two radii are the same
	
	public boolean equals(Object o)		// this method returns true only if the two circles have the same x,y coordinates and radius
	{
		ComparableCircles other=(ComparableCircles)o;	// again, place o into a ComparableCircle to prevent need for further casting
		if(x==other.getX()&&y==other.getY()&&r==other.getRadius()) return true;	// true only if the two Circles are the same
		else return false;
	}
	
}