public class ListProgram3 implements ListInterface{
    private static final int MAX_INITIAL_LIST = 10;
    private Object[] items;   // array of list items
    private int numItems;  // number of items in the list 
                           // numItems <= size of array
      
    public ListProgram3(){
	items = new Object[MAX_INITIAL_LIST];
	numItems = 0;
    }
   
    public boolean isEmpty(){
	return (numItems == 0);
    }
   
    public int size(){
	return numItems;
    }
   
    public void removeAll(){
	numItems = 0;
	items = new Object[MAX_INITIAL_LIST];
    }
   
    public void add (int index, Object item)
	throws ListIndexOutOfBoundsException{

	if(index<0 || index>numItems){
            throw new ListIndexOutOfBoundsException
		("List index is out of bounds in method add");
	}
	else{
  
	    if(numItems == items.length){  //resize
		Object[] newArray = new Object[2*items.length];
		for(int a=0; a< items.length;a++){
		    newArray[a]=items[a];
		}
		items=newArray;
	    }  // end if
         
	    // shift down
	    for (int pos = numItems-1; pos>=index; pos--){ 
		items[pos+1] = items[pos];
		items[index] = item;
		numItems++;
            } // end for
	} // end else
      
    } // end add
   
    public void remove (int index)
	throws ListIndexOutOfBoundsException{
	if(index<0 || index >numItems){
            throw new ListIndexOutOfBoundsException
		("List index is out of bounds in method remove");
	}
	else{
            for (int pos = index; pos <= numItems-2; pos++)
		items[pos] = items[pos+1];
         
	    numItems--;
	} // end else
    } //end remove
   
    public Object get (int index) 
	throws ListIndexOutOfBoundsException{
	if(index<0 || index>numItems){
            throw new ListIndexOutOfBoundsException
		("List index is out of bounds in method get");
	}
	else
            return items[index];
    } // end get
   
} // end ListProgram3