.. _part5:

Part 5
======

In part 5 we'll add an end to the quiz, but also fix a huge bug in the
program that makes the quiz way too easy.
  
  
What's the score?
-----------------

Let's add a score. We can increase it when the player gets an answer
correct and reduce it when they get one wrong.

Add this line near the top of your code under your questions lists: ::

  score = 0

Now in :code:`on_key_up` lets increase or decrease it. Change your code to add
these new lines: ::

  def on_key_up(key):
      global state, score        # <--- added score
      if key == keys.SPACE:
          state = 'play'

      if state == 'play' and keys.K_0 <= key <= keys.K_9:
          n,q = questions[0]
          answer = key.value - keys.K_0.value - 1
          if answer == n:
              print("Correct!")
              questions.pop(0)
              score += 1         # <--- New line
          else:
              print("Wrong, try again")
              score -= 1         # <--- New line
          print(score)           # <--- New line

You don't need to add the comments starting with :code:`#`.

Now test again, making sure to get some answers wrong to see the score
change.

The end sequence
----------------

Currently the code ends with an error after the last question because
we run out of questions and the code doesn't check for this, let's fix
this.

At the end of your :code:`on_key_up` function add this code to test
when there are no more questions: ::

  # No more questions left
  if not questions:
      state = 'end'

Now we can add an end sequence. In :code:`draw` add this code... ::

  # End sequence
  if state == 'end':
      screen.draw.text(
          "The end",
          color='white',
          midtop =(WIDTH/2, HEIGHT/2 - 50),
          fontsize=70,
      )

      screen.draw.text(
          "You scored %s" % score,
          color='white',
          midtop =(WIDTH/2, HEIGHT/2 + 50),
          fontsize=40,
      )

We can add more information too, let's tell the player how they did: ::

      if score == len(question_images):
          message = "You are a genius!"
      elif score < 0:
          message = "Oh dear!"
      else:
          message = "Hope you do better next time"

      screen.draw.text(
          message,
          color='white',
          midtop =(WIDTH/2, HEIGHT/2 + 150),
          fontsize=40,
      )      

Feel free to change those messages! 

Randomise the questions
-----------------------

You might have noticed a huge problem in our quiz... the answers are
always simply the sequence 1,2,3... let's fix this by randomising the
questions and answers.

We can do this by shuffling the question and answer lists, but we need
to shuffle them together otherwise they won't match up.

First, let's import the `random` library, put this line at the top of
your code: ::

  import random

Now let's `zip` the two lists together, shuffle them, then unzip them. Add
this just under where you set up your `answer_images` and `question_images`
lists: ::

  qa = list(zip(answer_images, question_images))
  random.shuffle(qa)
  answer_images, question_images = zip(*qa)

This puts the questions and answers in a random order, but it still
means that the answers are always 1,2,3...

So finally, let's shuffle the questions:

Under this line: ::

  questions = list(enumerate(question_images))

Add this line: ::
  
  random.shuffle(questions)

Right or wrong?
---------------

Let's tell the player in the game screen when they get something right or wrong.

[todo]