Question

我正在尝试编写一个简单的程序，计算并打印完美的正方形数字直到输入上限。我的代码是：

"""Print all the perfect squares from zero up to a given maximum."""

def read_bound():
   """Reads the upper bound from the standard input (keyboard).
      If the user enters something that is not a positive integer
      the function issues an error message and retries
      repeatedly"""
   upper_bound = None
   while upper_bound is None:
       line = input("Enter the upper bound: ")
       if line.isnumeric() and int(line) >= 0:
           upper_bound = int(line)
           return upper_bound
       else:
           print("You must enter a positive number.")



def is_perfect_square(num):
   """Return true if and only if num is a perfect square"""
   for num in range(2, upper_bound + 1):
       for candidate in range(1, num):
           if candidate * candidate == num:
               return True



def print_squares(upper_bound, squares):
   """Print a given list of all the squares up to a given upper bound"""


   print("The perfect squares up to {} are: ". format(upper_bound))
   for square in squares:
       print(square, end=' ')



def main():
   """Calling the functions"""
   upper_bound = read_bound()
   squares = []
   for num in range(2, upper_bound + 1):
       if is_perfect_square(num):
           squares.append(num)

   print_squares(upper_bound, squares)


   main()

但是，当我运行程序并输入任何有效数字时，我在builtins.NameError: name 'upper_bound' is not defined的行上收到错误，指出for num in range(2, upper_bound + 1):。是什么导致了这个问题，我该如何解决？

Answer 1

您的程序遇到问题＆＃34; is_perfect_square＆＃34;功能。你不需要＆＃34; upper_bound＆＃34; for循环，因为你已经在＆＃34; main＆＃34;功能。你的＆＃34; is_perfect_square＆＃34;功能应如下所示：

def is_perfect_square(num):
   """Return true if and only if num is a perfect square"""
   for candidate in range(1, num):
           if candidate * candidate == num:
               return True

在程序中定义变量的问题

1 个答案: