Lecture 18 --- Exercises
========================

Solutions to the problems below must be sent to Submitty for
automatic scoring.  A separate file must submitted for each problem.

#. Starting from the ``Point2d.py`` file you download from the
   Course Resources page of the Submitty site, please do the following:

   #. Write a new ``Point2d`` method called ``scale`` that takes as an
      input argument a ``Point2d`` object (``self``) and a numerical
      value (int or float) and multiples both the ``x`` and ``y``
      attributes by this value.

   #. Write a new ``Point2d`` method called ``dominates`` that two
      takes two ``Point2d`` objects and returns ``True`` if and only
      if the x coordinate of the first object is greater than that of
      the second object and the y coordinate of the first object is
      greater than that of the second object.

   #. The code to test these functions is commented out in the main
      code area.  Please remove this commenting, test your code, and
      submit your resulting ``Point2d.py`` file.  Call it ``Point2d_q1.py``

#. Copy your resulting file from the first question to a new file,
   perhaps called ``Point2d_q2.py``.

   #. Write and test the implementation of the method ``__str__``
      which returns a string created from the values of a ``Point2d``
      object.  For our purposes this is mostly used to create a string
      that can be printed.   Make sure you have this working before
      you proceed to the other parts of this exercise because they
      depend on it. If you are wondering about the format of a point,
      take a look at how we print out a point in Part 1.

   #. Write the implementation of the subtraction method ``__sub__``
      for the ``Point2d`` object.  Uncomment the code in the main area
      and test this in Spyder.

   #. Write the implementation of the method ``__mul__`` which is
      like the ``scale`` function you wrote for part 1, but it creates
      a new ``Point2d`` object.

   #. Write the implementation of the method ``__eq__`` which
      returns ``True`` if and only if the two ``Point2d`` objects have
      exactly the same ``x`` and ``y`` values.

   For each of these you should look at the commented out main code in
   the ``Point2d.py`` file you were provided to see how these
   methods should be used.  Uncomment this code, test your methods,
   and upload to Submitty when you are done.