class Account {
  public Account(int amt) {
    balance = amt;
  }

  public void deposit (int amt) {
    balance = balance + amt;
  }

  public int statement () {
    return balance;
  }

  private int balance;
}

class SparseNode {
  public SparseNode (int i, double v) {
    index = i;
    value = v;
  }
  int index;
  double value;
}

class Lecture10 {

 public static int [] copy (int [] v) {
     int [] result = new int [v.length];
     for (int i = 0; i < v.length; i++) {
       result[i] = v[i];
     }
     return result;
  }

  public static int [] resize (int [] v, int newSize, int init) {
      int [] result = new int [newSize];
      int k;
      for (k = 0; k < v.length; k++) {
	  result[k] = v[k];
      }
      for (; k < newSize; k++) {
         result[k] = init;
      }
      return result;
   }

  public static void printArray(String name, int [] a) {
     System.out.print(name + " = ");
     System.out.print("[ ");
     for (int i = 0; i < a.length-1; i++) {
       System.out.print(a[i] + ", ");
     }
     System.out.println(a[a.length-1] + " ]");
  }

  public static void main (String[] argv) {
    int [] b;    /* says x is an array, but it doesn't exist */
    // b[0] = 1;    /* error */
    b = new int [5];
    
    int [] a = new int [5];   // is initialized, but it's elements are not
    for (int i = 0; i < a.length; i++) {
       a[i] = i+1;
       b[i] = i+1;
    }

    int [] c = copy(a);
    printArray("a", a);
    printArray("b", b);
    printArray("c", c);

    System.out.println("a.equals(b) is: " + a.equals(b));
    System.out.println("b.equals(c) is: " + b.equals(c));
    System.out.println("a == b is: " + (a == b));
    System.out.println("b == c is: " + (b == c));
    System.out.println("assigning b = c;");
    b = c;
    System.out.println("a == b is: " + (a == b));
    System.out.println("b == c is: " + (b == c));

    int [] d = {1, 2, 3, 4, 5};
    // d = {2, 4, 6, 8, 10};  /* error */

    Account [] a1 = new Account [2]; // array of references to Accounts
    if (a1[0] == null) System.out.println("a1[0] is null");
    Account [] a2 = {new Account(100), new Account(200)};
    a2[0].deposit(50);

    Object [] e = new Object [2];
    e[0] = new Account(100);
    e[1] = new Integer(3);
    Object [] f = {new Account(100), new Integer(3)};
    
    printArray("d", d);
    d = resize(d, d.length*2+1, 9);
    printArray("d", d);
  }
}