# Lecture 18 — Exercises¶

Solutions to the problems below must be sent to Submitty for automatic scoring. A separate file must submitted for each problem. Solutions must be submitted by 4 pm on Tuesday, April 4.

1. Starting from the Point2d.py file you download from the Resources page of the Piazza site, please do the following:

1. 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.
2. 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.
3. The code to test these functions is commented out in the main code area. Please remove this commenting, test on Piazza, and submit your resulting Point2d.py file. Call it Point2d_q1.py
2. Copy your resulting file from the first question to a new file, perhaps called Point2d_q2.py.

1. 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.
2. Write the implementation of the subtraction method __sub__ for the Point2d object. Uncomment the code in the main area and test this in Wing IDE. Do NOT proceed to the next part of the question until you have this working!
3. 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.
4. 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.