import java.util.*;

class A implements Comparable {

    int data;

    public A (int d)
    {
	data = d;
    }

    public int compareTo (Object obj)
    {
	// Cast obj to A.
	// Then compare data to the data part of the parameter obj.
	// if data is equal than the parameter's data, return 0,
	// if less, return -1.
	// otherwise return 1.

	// WRITE YOUR CODE HERE
    }

    public String toString ()
    {
	return ""+data;
    }

}

public class CompInterfaceExample {

    public static void main (String[] argv)
    {
	A[] a = new A [3];
	a[0] = new A (5);
	a[1] = new A (4);
	a[2] = new A (5);
	System.out.println (a[0].compareTo(a[1]));   // Prints 1
	// Draw memory picture inside compareTo() just before returning here.
	System.out.println (a[0].compareTo(a[2]));   // Prints 0
	System.out.println (Arrays.toString(a));     // Original order.
	Arrays.sort (a);
	System.out.println (Arrays.toString(a));     // Sorted 4,5,5
    }

}