Python 面向对象习题(7/10)

import mathclass Fraction:    def __init__(self, numerator, denominator):        if denominator == 0:            raise ValueError(”分母不能为 0”)# 处理负号：统一放到分子上        if denominator < 0:            numerator = -numerator            denominator = -denominator # 约分        gcd = math.gcd(abs(numerator), abs(denominator))        self.numerator = numerator // gcd        self.denominator = denominator // gcd # -------- 运算符重载 --------    def __add__(self, other): # a/b + c/d = (a*d + c*b) / (b*d)        new_num = self.numerator * other.denominator + other.numerator * self.denominator        new_den = self.denominator * other.denominator        return Fraction(new_num, new_den)    def __sub__(self, other):        new_num = self.numerator * other.denominator - other.numerator * self.denominator        new_den = self.denominator * other.denominator        return Fraction(new_num, new_den)    def __mul__(self, other):        new_num = self.numerator * other.numerator        new_den = self.denominator * other.denominator        return Fraction(new_num, new_den)# -------- 比较运算 --------    def __eq__(self, other):        return self.numerator == other.numerator and self.denominator == other.denominator    def __lt__(self, other): # a/b < c/d  ⟺  a*d < c*b（分母已保证为正）        return self.numerator * other.denominator < other.numerator * self.denominator # -------- 字符串表示 --------    def __str__(self):        if self.denominator == 1:            return str(self.numerator)# 4/1 → ”4”        return f”{self.numerator}/{self.denominator}”    def __repr__(self):        return f”Fraction({self.numerator}, {self.denominator})” # -------- 类型转换 --------    def __float__(self):        return self.numerator / self.denominator# 测试f1 = Fraction(1, 2)f2 = Fraction(1, 3)f3 = Fraction(2, 3)f4 = Fraction(3, 4)# 运算print(f”{f1} + {f2} = {f1 + f2}”)# 1/2 + 1/3 = 5/6print(f”{f3} * {f4} = {f3 * f4}”)# 2/3 * 3/4 = 1/2（自动约分）print(f”{f1} - {f2} = {f1 - f2}”)# 1/2 - 1/3 = 1/6# 比较print(f”{f1} == {Fraction(2, 4)}: {f1 == Fraction(2, 4)}”)# True（2/4 约分后等于 1/2）print(f”{f2} < {f1}: {f2 < f1}”)# True（1/3 < 1/2）# 字符串与类型转换print(repr(f1))# Fraction(1, 2)print(f”float({f1}) = {float(f1)}”)# float(1/2) = 0.5print(f”float({f1 + f2}) = {float(f1 + f2):.4f}”)# float(5/6) = 0.8333# 整数分数的特殊显示print(Fraction(8, 2))# 4（分母为 1 时只显示分子）