import java.util.Scanner;
public class exc2 {

    private Object[] arr;
    private int count;
    private static final int INITIAL_CAPACITY = 4;

    /** Initializes the array-based list – allocate memory **/

    public exc2()
    {
        arr = new Object[INITIAL_CAPACITY];
        count = 0;
    }

    /**
     * @return the actual list length
     */

    public int getLength()
    {
        return count;
    }

    /**
     * Adds element to the list
     * @param item - the element you want to add
     */

    public void add(Object item)
    {
        add(count, item);
    }

    /**
     * Inserts the specified element at given position in this list
     * @param index -
     *        index at which the specified element is to be inserted
     * @param item -
     *        element to be inserted
     * @throws IndexOutOfBoundsException
     */
    public void add(int index, Object item)
    {

        if (index>count || index<0)
        {
            throw new IndexOutOfBoundsException("Invalid index: " + index);
        }

        Object[] extendedArr = arr;
        if (count + 1 == arr.length)
        {
            extendedArr = new Object[arr.length * 2];
        }

        System.arraycopy(arr, 0, extendedArr, 0, index);
        count++;
        System.arraycopy(arr, index, extendedArr, index+1, count-index-1);
        extendedArr[index] = item;
        arr = extendedArr;
    }

    /**
     * Returns the index of the first occurrence of the specified
     * element in this list.
     *
     * @param item - the element you are searching
     * @return the index of given element or -1 is not found
     */

    public int indexOf(Object item)
    {
        if (item == null) {
            for (int i = 0; i < arr.length; i++)
            {
                if (arr[i] == null) return i;
            }
        }
            else
            {
            for (int i = 0; i < arr.length; i++)

                if (item.equals(arr[i])) return i;
            }

        return -1;
    }

    /**
     * Clears the list
     */

    public void clear() {
        arr = new Object[0];
        count = 0;
    }

    /**
     * Checks if an element exists
     * @param item – the item to be checked
     * @return if the item exists
     */

    public boolean contains(Object item)
    {
        int index = indexOf(item);
        boolean found = (index != -1);
        return found;
    }

    /**
     * @return the object on given position
     */
    public Object elementAt(int index)
    {
        if (index>=count || index<0)
        {
            throw new IndexOutOfBoundsException("Invalid index: " + index);
        }
        return arr[index];
    }

    /**
     * Removes the element at the specified index
     * @param index - the index, whose element you want to remove
     * @return the removed element
     */

    public Object remove(int index)
    {
        if (index>=count || index<0)
        {
            throw new IndexOutOfBoundsException("Invalid index: " + index);
        }

        Object item = arr[index];
        System.arraycopy(arr, index+1, arr, index, count-index+1);
        arr[count - 1] = null;
        count--;
        return item;
    }



    /**
     * Removes the specified item and returns its index or -1
     * if item does not exists
     * @param item - the item you want to remove
    */

    public int remove(Object item)
    {
        int index = indexOf(item);

        if (index == -1)
        {
            return index;
        }
        System.arraycopy(arr, index+1, arr, index, count-index+1);
        count--;
        return index;
    }


   public static void main(String[] args)
    {

        exc2 shoppingList = new exc2 ();
        Scanner sc=new Scanner(System.in);

        while(true)
        {
            System.out.println();
            System.out.println("For ADD choose 1, for REMOVE choose 2, for END choose 3");
            int choice=sc.nextInt();

            if(choice==1)
            {
                System.out.println("The element you want to add:");
                String n=sc.next();

                if(shoppingList.contains(n)==false)
                {
                    shoppingList.add(n);

                    System.out.println();
                    System.out.println("Now your list contains:");
                    getList(shoppingList);

                    continue;

                } else
                {
                    System.out.println("The element is already in the list");
                    continue;
                }
            }

            if(choice==2)
            {
                System.out.println("The element you want to remove:");
                String n=sc.next();

                if(shoppingList.contains(n))
                {
                    shoppingList.remove(shoppingList.indexOf(n));

                    System.out.println();
                    System.out.println("Now your list contains:");
                    getList(shoppingList);

                    continue;

                } else
                {
                    System.out.println("No element to remove");
                    continue;
                }
            }

            if(choice==3)
            {
                System.out.println();
                System.out.println("Now your list contains:");
                getList(shoppingList);

                System.out.println("Program ended");
                break;
            }


        } // end while

        sc.close();

    } // end MAIN



    static void getList(exc2 shoppingList)
    {
        for(int i=0; i<shoppingList.getLength(); i++)
        {
            System.out.println(shoppingList.elementAt(i));
        }
    }

}