// Tile.java =====================================================
class Tile extends Rectangle implements Sortable
{
    public Tile(int x, int y, int w, int h, int zz)
    {
	super(x, y, w, h);
	z = zz;
    } // constructor

    public int compare(Sortable b)
    {
	Tile tb = (Tile)b;
	return z - tb.z;
    } // compare

    public String toString()
    {
	return super.toString() + " [z=" + z + "]";
    } // toString

    private int z;
} // Tile

// TileTest.java =====================================================

import java.awt.*;

public class TileTest
{
    public static void main(String[] args)
    {
	Tile[] a = new Tile[20];
	
	int i;
	for (i = 0; i < a.length; i ++)
	    a[i] = new Tile(i, i, 10, 20, (int)(100*Math.random()));
	SecondSort.sort(a);

	for (i = 0; i < a.length; i ++)
	    System.out.println(a[i]);
    } // main

} // TileTest

// SecondSort.java =====================================================
import java.util.*;

public class SecondSort
{   
   public static void sort(Sortable[] a)
   {
      int k;
      int n = a.length;
      k = 0;
      while (k < n)
      {
         int j = getSmallest(a, k);
         exchange(a, k, j);
         k ++;
      } // while
   } // Sort
 
   static void exchange(Sortable[] a, int k, int j)
   {
      Sortable temp;

      temp = a[k];
      a[k] = a[j];
      a[j] = temp;
   } // exchange

   static int getSmallest(Sortable[] a, int k)
   {
      Sortable s = a[k];
      int n = a.length;
      int minLoc = k;
      for (int i = k; i < n; i ++)
         if (s.compare(a[i]) > 0)  // s > a[i]
         {
            s = a[i];
            minLoc = i;
         }
       return minLoc;
   } // getSmallest
} // SecondSort

// Sortable.java =====================================================
public interface Sortable
{
   public abstract int compare(Sortable b);  // child class will implement it
}