/** Implementation of a list of strings using an array.
    @author Jed Yang, 2018-01-17
*/
public class CarlStringList implements List<String>
{
   // instance variables, private
   private String[] array;
   private int count;

   public CarlStringList()
   {
      array = new String[10];
      count = 0;
   }

   /** Live-code. */
   public void add(String item)
   {
      if (count >= array.length)
      {
         resizeArray();
      }
      array[count] = item;
      count++;
   }

   /** Worksheet. */
   public String get(int index)
   {
      // why should you use count and NOT array.length?
      if (index < 0 || index >= count)
      {
         throw new IndexOutOfBoundsException("index should be between 0 and size - 1");
      }
      return array[index];
   }

   /** Worksheet. */
   public void add(int index, String item)
   {
      if (count >= array.length)
      {
         resizeArray();
      }

      // why is this condition slightly different from the one in get?
      if (index < 0 || index > count)
      {
         throw new IndexOutOfBoundsException("index should be between 0 and size");
      }
      for (int i = count - 1; i >= index; i--)
      {
         array[i+1] = array[i];
      }
      array[index] = item;
      count++;
   }

   /** Worksheet. */
   private void resizeArray()
   {
      // why should you use array.length and NOT count?
      String[] newArray = new String[array.length*2];
      for (int i = 0; i < count; i++)
      {
         newArray[i] = array[i];
      }
      array = newArray;
   }

   /** Returns the number of elements in the list.
       @return size of the list
   */
   public int size()
   {
      return count;
   }

   /** Returns a comma-separated list of the elements.
       @return string representation
   */
   public String toString()
   {
      String s = "[";
      for (int i = 0; i < count; i++)
      {
         if (i > 0)
         {
            s += ",";
         }
         s += array[i];
      }
      return s + "]";
   }

   /** Demo and test of List methods. */
   public static void main(String[] args)
   {
      List<String> list1 = new CarlStringList();
      list1.add("a");
      list1.add("b");
      list1.add("c");
      list1.add("d");
      System.out.println("list should be [a,b,c,d]; actually: " + list1);
      System.out.println("length should be 4; actually: " + list1.size());

//      System.out.println(list1.get(7));
//*
      try
      {
         for (int i = 0; i < 23; i++)
         {
            list1.add("lots of stuff");
         }
      }
      catch (RuntimeException e)
      {
         System.err.println("too many things: " + e.getMessage());
      }
//*/
      System.out.println(list1);


      System.out.println("===============================================");

      List<String> list2 = new CarlStringList();
      list2.add(0, "a");
      list2.add(1, "c");
      list2.add(1, "b");
      list2.add(3, "d");
      System.out.println("list should be [a,b,c,d]; actually: " + list2);
      System.out.println("length should be 4; actually: " + list2.size());
//*/
   }
}