CPSC 103 Midterm
Monday March 22nd, 2021, 18:00 to 19:45
– You have 105 (90 for the exam and 15 for file uploading) minutes to write the 5 questions
on this examination. A total of 39 marks are available.
– This exam is to be handwritten. You are not allowed to type during the
exam. The only exception to this rule is if you are typing a message to the
invigilators or typing a post on our exam Piazza page.
– If we ask you to design a solution, we mean to design it using the appropriate design
recipes (i.e., HtDF, HtDD, or both) taught in CPSC 103.
– You are allowed to access Canvas, your notes, and (only to ask a question if you believe
you have found an error on the exam) private posts on the exam Piazza page, but not
other web sites. You are not allowed to contact people other than the course staff. You
are not allowed to use a calculator, Jupyter/Sygyzy or any other application on your
computer.
– You must write this exam under invigilation. Failure to do so will result in a grade of 0.
– If you are not directly writing on a printed copy of the exam, you do not need to copy
the given code onto your paper. For example, if we ask you to finish implementing a
function and we have already given you the signature/purpose/stub/tests, you just need
to clearly indicate which function the answer is meant for and then write your answer.
– Use the number of marks allocated to each question to help you determine how much
time you should spend on them.
– Good luck!
UNIVERSITY REGULATIONS:
– Each candidate should be prepared to produce, upon request, his/her UBC card.
– No candidate shall be permitted to enter the examination room after the expiration of
one half hour, or to leave during the first half hour of the examination.
– CAUTION: candidates guilty of any of the following, or similar, dishonest practices shall
be immediately dismissed from the examination and shall be liable to disciplinary action.
1. Having at the place of writing, or making use of, any books, papers or memoranda,
electronic equipment, or other memory aid or communication devices, other than
those authorised by the examiners.
2. Speaking or communicating with other candidates.
page 2 out of 14
Academic Integrity Pledge
We are taking this exam under unusual circumstances. It is important that this exam is
fair to all students, and that no student has an unfair advantage.
With that in mind, after reading the following paragraph, please affirm that you will
neither give assistance to, nor receive assistance from, another student about this exam.
Note that some students may be writing another version of this exam at a different time
than you are. So, be sure to keep quiet about its contents (for the next 72 hours).
I hereby pledge that I have read and will abide by the rules, regulations, and expectations
set out in the Academic Calendar, with particular attention paid to:
1. The Student Declaration
http://www.calendar.ubc.ca/vancouver/index.cfm?tree=3,285,0,0
2. The Academic Honesty and Standards
http://www.calendar.ubc.ca/vancouver/index.cfm?tree=3,286,0,0
3. The Student Conduct During Examinations
http://www.calendar.ubc.ca/vancouver/index.cfm?tree=3,41,90,0L
4. And any special rules for conduct as set out by the examiner.
You are free to choose whichever option you want below but do keep in mind that we
will not be able to grade your exam if you indicate that you disagree with this, or if you do
not answer this question.
What You Need To Do
If you agree to the conditions above, please write the following sentence and sign your
name next to the statement.
”I agree to abide by the exam’s academic integrity pledge.”
page 3 out of 14
1. [6 marks] Give the data type would be best suited for the following situations.
1. The Piazza posts that are yet to be answered
2. The colours of the rainbow
3. The planets in our solar system
4. The colour of a sweatshirt
5. The distance you can drive before you need to charge your car
6. Courses a student has taken at UBC
7. The position of a driver in a car race, considering that not all driver finish all race
(some may be out of the race due to mechanical issues or accidents).
8. The types of batteries sold at a store (e.g., AAA, AA, CR2032, etc.)
9. Whether or not you can dine in at a restaurant
10. Your grocery bill for the week
11. Email messages received by someone
12. The number of hours you slept last night
page 4 out of 14
2. [4 marks] Arty has written some messy code that doesn’t follow our HtDF recipe and
doesn’t quite work. Fix this code so it can accomplish the task listed in the purpose.
The data definition is correct. The errors are in HtDF.
Identify the line number where each error is found and describe how you would fix each
error (if you believe a line should be removed, write its number and LINE SHOULD BE
REMOVED after it).
01. from cs103 import *
02. from typing import List
03.
04. # List[str]
05. # a list of strings
06.
07. L0 = []
08. L1 = ["apple"]
09. L2 = ["apple, "orange", "banana", "Anne", "Oswald", "berry"]
10.
11. @typecheck
12. def fn_for_los(los: List[str]) -> ...:
13. # description of the accumulator
14. acc = ... # type: ...
15.
16. for s in los:
17. acc = ...(s, acc)
18.
19. return ...(acc)
page 5 out of 14
01. @typecheck
02. def find_words_starting_with_a_and_o(los: List[str]):
03. """
04. Returns all the words that start with an "a" or an "o",
05. in lowercase or uppercase.
06. """
07. # return [] # stub
08. # template from List[str]
09. # all words that start with a or o seen so far
10. acc = [] # type: List
11.
12. for s in los:
13. if s[0] == "a" or "s[0] == A":
14. acc.append("a")
15. return acc
16.
17. for s in los:
18. if s[0] == "o" or s[0] == "O":
19. acc.append("o")
20.
21. return acc
22.
23. start_testing()
24.
25. expect(find_words_starting_with_a_and_o(L0), [])
26. expect(find_words_starting_with_a_and_o(L2), ["apple, "orange",
"Anne", "Oswald"])
27.
28. summary()
page 6 out of 14
The rest of the questions on the exam are based on an Animal Hospital that treats cats
and dogs. Each animal has a name, colour, age, gender, species (dog or cat), weight, and
a status to indicate whether or not it was rescued from the street.
3. [9 marks] Complete the data definitions used in this Animal Hospital.
from cs103 import *
from enum import Enum
from typing import NamedTuple
from typing import List
Species = Enum(’Species’, [’cat’, ’dog’])
# interp. An animal’s species. It can be a cat or a dog.
# Examples are redundant for enumerations
# template based on Enumeration
@typecheck
def fn_for_species(s: Species) -> ...:
if s == Species.cat:
return ...
elif s == Species.dog:
return ...
Gender = Enum(’Gender’, [’male’, ’female’])
# interp. of an animal gender
# examples are redundant for enumerations
# template based on Enumeration
@typecheck
def fn_for_gender(g: Gender) -> ...:
if g == Gender.male:
return ...
elif g == Gender.female:
return ...
page 7 out of 14
Animal = NamedTuple(’Animal’,
# interp. An animal has a name, colour, age (in years),
# gender, species, weight (in kg),
# and if it is rescued from the street or not.
A1 =
A2 =
A3 =
# template based on
@typecheck
def fn_for_animal(a: Animal) -> ...:
page 8 out of 14
# List[Animal]
# interp. A list of animals in an animal hospital
L0 = []
L1 = [A1, A2, A3]
# template based on arbitrary-sized and reference rule
@typecheck
def fn_for_loa(loa: List[Animal]) -> ...:
# description of the accumulator
acc = ... # type: ...
for a in loa:
acc = ...(fn_for_animal(a), acc)
return ...(acc)
page 9 out of 14
4. [13 marks] The following function examines a list of animals determine whether it
contains a male animal that is the given age and colour. Complete the helper functions
and add new ones if needed. You can assume has male dog() is complete and correct.
Assume the tests for all functions are present, complete, and correct.
Hint: You have to create at least 2 new helper functions.
@typecheck
def has_male_dog(animals: List[Animal], age: int, color: str) -> bool:
"""
Returns True if there is at least one male dog in animals that
has the given color and age; False otherwise.
"""
# return True # stub
# template copied from List[Animal] with 2 additional parameters
for a in animals:
if is_animal_male(a) and is_animal_dog(a) and
has_age(a, age) and has_color(a, color):
return True
return False
@typecheck
def is_animal_male(a: Animal) -> bool:
"""
Returns True if a is male; False otherwise.
"""
# return True # stub
page 10 out of 14
@typecheck
def is_animal_dog(a: Animal) -> bool:
"""
Returns True if a is a dog; False otherwise.
"""
# return True # stub
@typecheck
def has_age(a: Animal, age: int) -> bool:
"""
Return True if a is exactly age years old
"""
# return True # stub
page 11 out of 14
@typecheck
def has_color(a: Animal, colour: str) -> bool:
"""
return True if a’s colour is colour
"""
# return True # stub
start_testing()
# Assume the set of tests is correct and complete
summary()
page 12 out of 14
5. [7 marks] The following function should return all female cats heavier than a given
weight. It is possible that your answer will not call every helper function listed in this
question. You cannot write any other helper functions for this question. Only use
what you are given. You are not required to complete the helpers; you only need
to complete find female cats(). You can assume that the tests are complete and
correct for all functions.
@typecheck
def find_female_cats(
"""
Returns a list of female cats that are
strictly heavier than weight.
"""
# return [] # stub
# template based on composition
page 13 out of 14
@typecheck
def find_all_cats(animals: List[Animal]) -> List[Animal]:
"""
Returns all cats in animals.
"""
return [] # stub
@typecheck
def is_animal_cat(a: Animal) -> bool:
"""
Returns True if a is a cat; False otherwise.
"""
return True # stub
@typecheck
def is_cat(s: Species) -> bool:
"""
Returns True if s is a cat; False otherwise.
"""
return True # stub
@typecheck
def find_all_female(animals: List[Animal]) -> List[Animal]:
"""
Returns all female animals.
"""
return [] # stub
@typecheck
def is_animal_female(a: Animal) -> bool:
"""
Returns True if a is female; False otherwise.
"""
return True
@typecheck
def is_female(g: Gender) -> bool:
"""
Returns True if g represents a female; False otherwise.
"""
return True
page 14 out of 14
@typecheck
def find_animals_weight(animals: List[Animal], weight: float)
-> List[Animal]:
"""
Returns all animals that are strictly heavier than weight.
"""
return [] # stub
@typecheck
def weight_more_than(a: Animal, weight: float) -> bool:
"""
Returns True if a is strictly heavier than weight;
False otherwise.
"""
return True # stub
start_testing()
# Assume the tests are complete and correct
summary()
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