/*
 *          File: array.tem
 *        Author: Robert I. Pitts <rip@cs.bu.edu> 
 * Last Modified: Fall 2000
 *         Topic: Templates
 * -----------------------------------------------------
 *
 * This is the implementation of a class representing a resizable array.
 *
 */

/*
 * Constructor
 * -------------------------
 * The array should be initially empty, so we need not allocate any
 * space.  We initialize the pointer and set the 'sz' (size) to zero.
 */

template <class Item>
Array<Item>::Array()
{
  contents = NULL;
  sz = 0;
}


/* Destructor
 * -----------------------
 * This deallocates all memory associated with the array.
 */

template <class Item>
Array<Item>::~Array()
{
  delete [] contents;
  // Reset data, just in case.
  contents = NULL;
  sz = 0;
}

/*
 * Function: resize
 * -----------------------
 * Make the array the requested size.  If old size is larger
 * than new size, some elements will be lost.  If the new
 * size is larger, the additional elements created will have
 * no initial value (unless elements have a default constructor).
 * We only use as much space as requested for the internal,
 * dynamically-allocated array, although we could be smarter
 * about allocation.  Currently, it does not check to make
 * sure 'new_size' is valid.
 */

template <class Item>
void Array<Item>::resize(int new_size)
{
  if (new_size != sz) {
    // New space
    Item *new_contents = new Item[new_size];

    // Copy as much of old contents as needed
    for (int i = 0; i < sz && i < new_size; i++) {
      new_contents[i] = contents[i];
    }

    delete contents;  // Get rid of old array.

    contents = new_contents;
    sz = new_size;
  }
}

/*
 * Function: operator []
 * -----------------------
 * Allows access to a particular element in the array.
 * Currently, it does no range checking of the index.
 */

template <class Item>
Item &Array<Item>::operator [](int index)
{
  return contents[index];
}

/*
 * Function: size
 * -----------------------
 * Returns the current size of the array.
 */

template <class Item>
int Array<Item>::size() const
{
  return sz;
}