*********
Iterators
*********

* Feel free to use your laptop
* You are strongly encourage to work with others

    * When you get stuck, ask those sitting around you for help
    * Get used to working together in the labs
    * Peer teaching and peer learning has been empirically shown to be very effective


Playing with Iterators
======================

The goal is to redefine stacks and queues such that the collections are iterable based on the details discussed in the
:doc:`Iterators Topic </topics/iterators/iterators>`.


Create an Array Iterator
------------------------

#. Create an ``ArrayIterator`` class that implements the ``Iterator`` interface


.. note::

    Obviously one can simply download the :download:`ArrayIterator <../../../main/java/ArrayIterator.java>` code, but
    this defeats the purpose of the lab. Instead, slowly and deliberately implement each method and take the time to
    understand the details.



Create an Iterable Stack
------------------------

#. Download the :download:`Stack interface <../../../main/java/Stack.java>` and add it to the project
#. Modify the interface such that ``Stack`` extends ``Iterable``
#. Add the required ``iterator`` method to the interface

#. Download the :download:`ArrayStack <../../../main/java/ArrayStack.java>` class and add it to the project
#. Modify the ``ArrayStack`` such that it implements the ``iterator`` method

    * Simply have it return the ``ArrayIterator``


#. Modify the existing ``toString`` method such that it uses an iterator

    * Refer to the ``toString`` from the :download:`ArraySortedBag <../../../main/java/ArraySortedBag.java>` for help


.. note::

    What order are the elements returned by the iterator for the ``ArrayStack``? Should it start at index ``0`` or at
    the top?

    

Create an Iterable Queue
------------------------

#. Download the :download:`Queue interface <../../../main/java/Queue.java>` and add it to the project
#. Modify the interface such that ``Queue`` extends ``Iterable``
#. Add the required ``iterator`` method to the interface

#. Download the :download:`ArrayQueue <../../../main/java/ArrayQueue.java>` class and add it to the project
#. Modify the ``ArrayQueue`` such that it implements the ``iterator`` method
#. Modify the existing ``toString`` method such that it uses an iterator



Make the Linked Stack and Queue Iterable
----------------------------------------

Repeat the same ideas for the :download:`LinkedStack <../../../main/java/LinkedStack.java>` and
:download:`LinkedQueue <../../../main/java/LinkedQueue.java>`.


Improve ``equals``
------------------

The current implementations of the ``Stack`` and ``Queue`` objects are only able to be equal to instances of the exact
same type. For example, it is currently only possible to have an ``ArrayStack`` be equal to another ``ArrayStack``.
However, this is less than ideal as it should be possible to check equality between ``Stack`` objects, regardless of
their specific implementation. In other words, it should be possible for an ``ArrayStack`` to be equal to a
``LinkedStack``.

Modify the existing ``equals`` methods within the various stack and queue implementations such that it is possible for
``Stack`` and ``Queue`` instances to be equal, regardless of their specific implementation.



Kattis Problems
===============

#. https://open.kattis.com/problems/quadrant
#. https://open.kattis.com/problems/judgingmoose
#. https://open.kattis.com/problems/timeloop
#. https://open.kattis.com/problems/oddities
#. https://open.kattis.com/problems/fizzbuzz
#. https://open.kattis.com/problems/twostones
#. https://open.kattis.com/problems/spavanac
#. https://open.kattis.com/problems/cetvrta
#. https://open.kattis.com/problems/bus
#. https://open.kattis.com/problems/timeloop
#. https://open.kattis.com/problems/oddities
#. https://open.kattis.com/problems/fizzbuzz
#. https://open.kattis.com/problems/sibice
#. https://open.kattis.com/problems/datum
#. https://open.kattis.com/problems/dicecup
#. https://open.kattis.com/problems/autori
#. https://open.kattis.com/problems/apaxiaaans
#. https://open.kattis.com/problems/hissingmicrophone
#. https://open.kattis.com/problems/trik
#. https://open.kattis.com/problems/pot
#. https://open.kattis.com/problems/filip
#. https://open.kattis.com/problems/reversebinary
#. https://open.kattis.com/problems/sevenwonders
#. https://open.kattis.com/problems/zamka
#. https://open.kattis.com/problems/bijele
#. https://open.kattis.com/problems/cold
#. https://open.kattis.com/problems/nastyhacks
#. https://open.kattis.com/problems/grassseed
#. https://open.kattis.com/problems/pet
#. https://open.kattis.com/problems/batterup
#. https://open.kattis.com/problems/aboveaverage
#. https://open.kattis.com/problems/icpcawards
#. https://open.kattis.com/problems/quickbrownfox
#. https://open.kattis.com/problems/nodup
#. https://open.kattis.com/problems/conundrum
#. https://open.kattis.com/problems/bela
#. https://open.kattis.com/problems/kornislav