import java.util.*;

public class arraycopy
{
   
   public static void resetArray(int[] a)
   {
      int x;
      
      for ( x = 0; x < a.length; x++)
	a[x] = 0;
   }
   
   public static void printArray(int[] a)
   {
      int x, len = a.length;

      for (x = 0; x < len; x++)
      {
	 System.out.println("Value at index " + x +
			    " is " + a[x]);
      }
      
   }
   
   public static void main(String[] args)
   {
      int[] ia1 = new int[5];
      int[] ia2 = new int[5];
      int x;
      
      // initialize the array to random numbers.
      for (x = 0; x < ia1.length; x++)
      {
	 ia1[x] = (int) (Math.random() * 100 + 1);
      }

      // display array contents.
      System.out.println("\nContents of ia1");
      printArray(ia1);
      
      // deep copy ia2 into ia1 with for loop
      System.out.println("\nUsing for loop");
      for (x = 0; x < ia1.length; x++)
	ia2[x] = ia1[x];
      
      printArray(ia2);

      // deep copy with arraycopy()
      resetArray(ia2);
      System.out.println("\nUsing System.arraycopy()");
      System.arraycopy(ia1, 0, ia2, 0, ia1.length);
      printArray(ia2);
      
      // shallow copy ia2 to ia1
      System.out.println("\nBefore shallow copy");
      System.out.println("ia1 hash = " + System.identityHashCode(ia1));
      System.out.println("ia2 hash = " + System.identityHashCode(ia2));
      
      ia2 = ia1;
      
      System.out.println("\nAfter shallow copy");
      System.out.println("ia1 hash = " + System.identityHashCode(ia1));
      System.out.println("ia2 hash = " + System.identityHashCode(ia2));

      // Use Arrays.copyOf() - JDK 6
      System.out.println("\nUsing Arrays.copyOf() with ia1.length*2");
      ia2 = Arrays.copyOf(ia1, ia1.length * 2);
      printArray(ia2);
      
   }
}