当我按run时，Python代码没有输入。我怎样才能解决这个问题？

这是我的家庭作业：

这是我的代码：

from math import gcd

class Rational:

   def __init__ (self, numerator, denominator):
        self.numerator = numerator
        self.denominator = denominator
        red = self.reduce()
        self.numerator = red.numerator
        self.denominator = red.denominator

   def add(self, other):
       self.numerator = self.numerator * other.denominator + other.numerator * self.denominator
       self.denominator = self.denominator * other.denominator
       
   def mul(self, other):
       self.numerator = self.numerator * other.numerator
       self.denominator = self.denominator * other.denominator

   def reduce(self):  
       if self.numerator == 0 : 
           return 0

       nd_gcd = gcd(self.denominator%self.numerator,self.numerator)
       if nd_gcd == 1:
          return self

       return Rational(int(self.numerator//nd_gcd), int(self.denominator//nd_gcd))

---

但当我单击run时，没有输出。我不知道怎么修理它。任何帮助都将不胜感激

您需要实例化您的类。我还添加了一个str函数，用于打印类：

from math import gcd

class Rational:

    def __init__ (self, numerator, denominator):
        self.numerator = numerator
        self.denominator = denominator
        red = self.reduce()
        self.numerator = red.numerator
        self.denominator = red.denominator

    def __str__(self):
        return str(self.numerator) + "/" + str(self.denominator)
    
    def add(self, other):
        self.numerator = self.numerator * other.denominator + other.numerator * self.denominator
        self.denominator = self.denominator * other.denominator
       
    def mul(self, other):
        self.numerator = self.numerator * other.numerator
        self.denominator = self.denominator * other.denominator

    def reduce(self):  
        if self.numerator == 0 : 
            return 0

        nd_gcd = gcd(self.denominator%self.numerator,self.numerator)
       
        if nd_gcd == 1:
            return self

        return Rational(int(self.numerator//nd_gcd), int(self.denominator//nd_gcd))



a = Rational(2, 5)
b = Rational(2, 7)

a.add(b)
print(a)

---

您还应该在相加和相乘后减少。

您只声明了函数和类。您没有实例化它。所以就没有输出了。@Soban我不是那么聪明，而且我真的不擅长Python。我该怎么做？你希望得到什么样的输出？你为什么期望产出？您的任务描述没有说它期望或应该产生任何输出。@Mistermiagi我认为说明说它应该以分数的简化形式输出答案。据我所知（搜索图片而不是文本不是最佳选择），这里显示的说明没有说任何这类事情。