// TestCopyArray.java: Demonstrate copying arrays
// Adapted from example in Liang's textbook

public class TestCopyArray {
  /** Main method */
  public static void main(String[] args) {
    // Create an array and assign values
    int[] list1 = {0, 1, 2, 3, 4 ,5};
    // Create an array with default values of 0
    int[] list2 = new int[list1.length];

    // Display list1 and list2
    System.out.println("After declaring and initializing list1 and list2");
    printList("list1 is ", list1);
    printList("list2 is ", list2);

    // Assign array list1 to array list2;
    // NOTE THAT THIS IS NOT A GOOD IDEA!!!
    list2 = list1;

    // Display list1 and list2
    System.out.println("\nBefore modifying list1 but after attempting to set them equal");
    printList("list1 is ", list1);
    printList("list2 is ", list2);

    // Modify list1 -- AND SEE WHAT HAPPENS TO list2!
    for (int i = 0; i < list1.length; i++)
      list1[i] = 0;

    // Display list1 and list2 after modifying list1
    System.out.println("\nAfter modifying list1, note what happened to list2!");
    printList("list1 is ", list1);
    printList("list2 is ", list2);

	// Here is a better way to do this:
    int[] list3 = {0, 1, 2, 3, 4 ,5};

    // Create an array with default values of 0
    int[] list4 = new int[list3.length];

	for (int j=0; j < list3.length; j++)
		list4[j] = list3[j];

    // Display list3 and list4 again after copying list1 to list2
    System.out.println("\nAfter copying list3 to list4, each element at a time");
    printList("list3 is ", list3);
    printList("list4 is ", list4);
    
    // Modify list3 -- AND SEE WHAT HAPPENS TO list4!
    for (int i = 0; i < list3.length; i++)
      list3[i] = 0;

    System.out.println("\nAfter modifying list 3:");
    printList("list3 is ", list3);
    printList("list4 is ", list4);

  }

  /** The method for printing a list */
  public static void printList(String s, int[] list) {
    System.out.print(s + " ");
    for (int i = 0; i < list.length; i++)
      System.out.print(list[i] + " ");
    System.out.println();
  }
}