fractions for Problem Solving with Algorithms and Data Structures

fractions.py

import unittest

def gcd(m, n):
    while m % n != 0:
        oldm = m
        oldn = n

        m = oldn
        n = oldm % oldn
    return n


class Fraction:
    def __init__(self, top, bottom):
        self.num = top
        self.den = bottom

    def __str__(self):
        return str(self.num) + "/" + str(self.den)

    def show(self):
        print(self.num, "/", self.den)

    def __add__(self, otherfraction):
        newnum = self.num * otherfraction.den + \
                 self.den * otherfraction.num
        newden = self.den * otherfraction.den
        common = gcd(newnum, newden)
        return Fraction(newnum // common, newden // common)

    def __truediv__(self, otherfraction):
        firstmul = self.num * otherfraction.den
        secondmul = self.den * otherfraction.num
        return Fraction(firstmul, secondmul)

    def __mul__(self, otherfraction):
        firstmul = self.num * otherfraction.num
        secondmul = self.den * otherfraction.den
        return Fraction(firstmul, secondmul)
    
    def __sub__(self, otherfraction):
        newnum = self.num * otherfraction.den - \
                 self.den * otherfraction.num
        newden = self.den * otherfraction.den
        common = gcd(newnum, newden)
        return Fraction(newnum // common, newden // common)

    def __eq__(self, other):
        firstnum = self.num * other.den
        secondnum = other.num * self.den
        return firstnum == secondnum
    
    def __gt__(self, other):
        'self > otherfraction'
        firstnum = self.num * other.den
        secondnum = other.num * self.den
        return firstnum > secondnum

    def __lt__(self, other):
        'self < otherfraction'
        firstnum = self.num * other.den
        secondnum = other.num * self.den
        return firstnum < secondnum





class TestFractionFunction(unittest.TestCase):
    def setUp(self):
        self.x = Fraction(1, 2)
        self.y = Fraction(2, 3)

    def test_add(self):
        self.assertEqual(self.x + self.y, Fraction(7,6))

    def test_sub(self):
        self.assertEqual(self.x - self.y, Fraction(-1,6))

    def test_mul(self):
        self.assertEqual(self.x * self.y, Fraction(1,3))

    def test_div(self):
        self.assertEqual(self.x / self.y, Fraction(3,4))

    def test_eq(self):
        self.assertEqual(self.x == self.y, False)

    def test_gt(self):
        self.assertEqual(self.x > self.y, False)

    def test_lt(self):
        self.assertEqual(self.x < self.y, True)


if __name__ == '__main__':
    unittest.main()