Description
Assignment
This assignment should be completed as a pair of Python source (.py) files with the following
names:
‚ main.py
‚ hw5_fraction.py modified from hw5_fraction.py (avaialble on Carmen)
Each question (including the Challenge Activities) has an associated TODO comment in the
template files.
(1) Implement the Fraction class in hw5_fraction.py.
(2) Create a file called main.py in the same directory as hw5_fraction.py. In the new
file, import Fraction into main.py in two ways:
‚ By importing the entire module hw5_fraction into main.py
‚ By importing only the class Fraction into main.py
(3) Pick one of those imports and give the imported entity a shorter name.
(4) Write some code in main.py to test your implementation of the Fraction class. Here
are a few suggested classes of test cases:
‚ Initialization and printing of a fraction with value 0. Hint: Such a fraction should
have denominator 1 in reduced form.
‚ Initialization and printing of a fraction with numerator and denominator that are
relatively prime.
‚ Initialization and printing of a fraction with nonzero numerator and denominator that
are not relatively prime.
‚ The sum of two fractions with the same denominator.
‚ The sum of two fractions with different denominators.
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(5) Augment the Fraction class with a method to enable Fractions to be compared with
the less-than operator <. (6) Use functools.total_ordering to enable Fractions to be compared with any of the comparison operators in Python. (7) Add code to test this new functionality of Fraction. (8) Move your test code from main.py to the end of hw5_fraction.py such that they are only executed if hw5_fraction.py is invoked as the main program by the Python interpreter. At this point, the file main.py should only have import statements in it. Challenge Activities Some homeworks (such as this one) will have additional challenge activities. These activities do not contribute to your grade, but they are problems that I find interesting or challenging. (9) Augment the Fraction class with methods to support integer exponentiation with the ** operator and absolute value with the built-in abs function. (10) Augment the Fraction class with a method to support conversion to bool. Hint: by Python convention for numeric types, the value 0 should evaluate to False, and any other value should evaluate to True. (11) Augment the Fraction class with a class method called from_str(cls, s: str) -> Fraction.
def from_str(cls, n: str) -> ’Fraction’:
“””Produces a fraction from string n.
Requires n is in one of two forms.
Either n is the string representation of a fraction
(e.g., ’5/3’ or ’-18/36’),
or n is the string representation of a decimal number
(e.g., ’47.625’ or ’-8.3333’).
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“””
(12) Modify the __init__ method to take either two int arguments or a single str
argument, treated as it is in from_str.
(13) Does your implementation of Fraction “gracefully” handle negative numbers? In
particular, the statement Fraction(2, -4) should produce the fraction -1/2 and
Fraction(-5,3).mixed_number() should return “-1 2/3”. If this is the output
that you get: great! If not, fix your Fraction class to handle it.
Submission
To submit this assignment, upload a .zip file containing both Python files to the “Homework 5”
assignment on Carmen. As always, be sure to note all group members who contributed to the
assignment and what those contributions were.
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