Class representatives
=====================

Save all functions into the same file named ``representatives.py``.

The students of a class have chosen their class representative. Votes
have been stored in a list where each element is one vote: a student
name. Write the following functions:

.. py:function:: votes_cand(lvotes, lcand)

   Given a :class:`list` of votes, ``lvotes``, and a :class:`list` of
   the possible candidate names, ``lcand``, (all students in the
   class), returns a dictionary (:class:`dict`). In this dictionary,
   keys are all possible candidates and values are the number of votes
   that each candidate has obtained. In addition, the dictionary must
   have the key ``'null'`` that will have the number of null votes as
   value, i.e., the votes that do not correspond to any candidate. For
   example:

   .. literalinclude:: test-votes_cand.txt
       :language: python
       :lines: 3-

.. Note::

   More tests are provided in :download:`test-votes_cand.txt`.

.. py:function:: quant_votes(dvotes, name)

   Given a dictionary such as that obtained by function
   :py:func:`votes_cand`, and a name of a candidate
   (:class:`str`), return a :class:`tuple` with a Boolean
   (:class:`bool`) and an integer (:class:`int`). If the candidate
   name is in the given dictionary, the Boolean will be ``True`` and
   the integer will be the number of votes that this candidate has
   obtained; otherwise, the Boolean will be ``False`` and the integer
   ``-1``.

   .. literalinclude:: test-quant_votes.txt
       :language: python
       :lines: 3-

.. Note::

   More tests are provided in :download:`test-quant_votes.txt`.

.. py:function:: percent_null(dvotes)

   Given a dictionary such as that obtained by function
   :py:func:`votes_cand`, return the percentage of null votes with
   respect to the total votes (:class:`float`). Suppose that there is
   at least one vote in the dictionary. For example,

   .. literalinclude:: test-percent_null.txt
       :language: python
       :lines: 3-
               
.. Note::

   More tests are provided in :download:`test-percent_null.txt`.

.. py:function:: win(dvotes)

   Given a dictionary such as that obtained by function
   :py:func:`votes_cand`, returns a :class:`list`, sorted
   alphabetically, with the names of the winners, i.e., those
   candidates who have obtained the maximum number of votes. The list
   will have more than one element in case of a tie. For example,

    .. literalinclude:: test-win.txt
       :language: python
       :lines: 3-
               
.. Note::

   More tests are provided in :download:`test-win.txt`.


.. rubric:: Solution

A solution is provided in the :download:`representatives.py
<solutions/representatives.py>`.