USE PYTHON3; DO NOT IMPORT ANY PACKAGES

Please do all of number 1,and do not add or remove any parameters. Thank you!

1.

a) The Course class is used to represent a course at UCSD. It has the following four instance attributes:

• course_code (str): the code associated with the course, e.g. "DSC20"

• name (str): the name of the course, e.g. "Intro to Programming"

• instructor (str): the name of the instructor, e.g. "Marina Langlois"

• enrollment_limit (int): the maximum number of students allowed to enroll in the course

• is_upperdiv (boolean): either True or False, indicates whether the course is an upper division course

In this question, you will implement the string representation function __str__(), and object representation function __repr__() of the Course class. We have implemented the constructor for you.

Let's say that we have initialized a Course object:

>>> dsc20 = Course("DSC20", "Intro to Programming", "Marina Langlois", 150, False)

1. After implementing __str__(), we can use print() to print out the string representation of a Course object in a format like this:

>>> print(dsc20)

DSC20: Intro to Programming, a lower-division course instructed by Marina Langlois, allows 150 students to enroll.

Note that when is_upperdiv is True, it's "an upper-division" in the string representation, rather than "a lower-division".

2. After implementing __repr__(), simply typing the object variable name in the command line will give you a piece of code that initializes a Course object:

>>> dsc20

Course('DSC20', 'Intro to Programming', 'Marina Langlois', 150, False)

Please see the doctests for more examples.

Hint:

str.format() is a really helpful function for formatting strings.

def course_doctests():

""" Doctests for Course. >>> dsc20 = Course("DSC20", "Intro to Programming", "Marina Langlois", ... 150, False) >>> print(dsc20) DSC20: Intro to Programming, a lower-division course instructed by Marina Langlois, allows 150 students to enroll. >>> dsc20 Course('DSC20', 'Intro to Programming', 'Marina Langlois', 150, False)

>>> dsc106 = Course("DSC106", "Intro to Data Visualization", ... "Thomas Powell", 100, True) >>> print(dsc106) DSC106: Intro to Data Visualization, an upper-division course instructed by Thomas Powell, allows 100 students to enroll. >>> dsc106 Course('DSC106', 'Intro to Data Visualization', 'Thomas Powell', 100, True)

# TODO: Create three additional Course instances, and for each object create # a set of doctests similar to the above ones. """ return

class Course: """ # TODO: Add class description # """

def __init__(self, course_code, name, instructor, \ enrollment_limit, is_upperdiv): """ Constructor of Course class. DO NOT CHANGE THIS. """ self.course_code = course_code self.name = name self.instructor = instructor self.enrollment_limit = enrollment_limit self.is_upperdiv = is_upperdiv

def __str__(self): """ # TODO: Add method description # """ # YOUR CODE GOES HERE # return ...

def __repr__(self): """ # TODO: Add method description # """ # YOUR CODE GOES HERE # return ...

b)

Write a recursive function that takes two sequences of numeric values (main and sub), and calculate two kinds of sum of the main sequence:

1. Sum of intersection: the sum of all numbers in the main sequence that also appear in the sub sequence.

2. Sum of differences: the sum of all numbers in the main sequence that do not appear in the sub sequence.

This function should return a tuple of (sum_of_intersection, sum_of_difference), if the main sequence is empty, return (0, 0).

You CANNOT use sum(), range(), or any loops/list comprehensions.

def find_two_sums_rec(main, sub):

"""

>>> main_seq = [0, 1, 1, 2, 3, 3, 4, 5, 5]

>>> find_two_sums_rec(main_seq, [])

(0, 24)

>>> find_two_sums_rec(main_seq, [1, 2])

(4, 20)

>>> find_two_sums_rec(main_seq, [3, 4, 5])

(20, 4)

"""

# YOUR CODE GOES HERE #