python - 我的 'lowest common multiple' 程序挂起，没有输出答案

Question

我一直在尝试更多地参与编程，所以我一直在尝试制作一个简单的程序，将两个数字作为输入，并计算最小公倍数。我是用 Python 做的，因为我不知道如何用 Java 输入。现在发生的是程序在我输入数字后挂起，没有任何反应。这里的任何指针将不胜感激。谢谢。

#LCM Calculator
#Author: Ethan Houston
#Language: Python
#Date: 2013-12-27
#Function: Program takes 2 numbers as input, and finds the lowest number
# that goes into each of them

def lcmCalculator(one, two):
    """ takes two numbers as input, computes a number that evenly 
        divides both numbers """
    counter = 2 #this is the number that the program tried to divide each number by.
                #it increases by 1 if it doesn't divide evenly with both numbers.
    while True:
        if one % counter == 0 and two % counter == 0:
            print counter
            break
        else:
            counter += 1

print "\nThis program takes two numbers and computes the LCM of them...\n"

first_number = input("Enter your first number: ")
second_number = input("Enter your second number: ")

print lcmCalculator(first_number, second_number)

Answer 1

你的逻辑有点不对。这一行:

if one % counter == 0 and two % counter == 0:

需要这样改写:

if counter % one == 0 and counter % two == 0:

此外，您的函数应该返回 counter 而不是打印它。这有两个好处:

1. 它会阻止脚本在最后打印None(函数的默认返回值)。

2. 它允许您压缩这两行:

   print counter
   break
   

   变成一个:

   return counter
   

最后，正如@FMc 在评论中指出的那样，您可以通过做两件事来提高函数的效率:

1. 从函数的两个参数中较小的一个开始counter。

2. 按此值递增 counter。

---

以下是解决所有这些问题的脚本版本:

#LCM Calculator
#Author: Ethan Houston
#Language: Python
#Date: 2013-12-27
#Function: Program takes 2 numbers as input, and finds the lowest number
# that goes into each of them

def lcmCalculator(one, two):
    """ takes two numbers as input, computes a number that evenly 
        divides both numbers """
    counter = min_inp = min(one, two)
    while True:
        if counter % one == 0 and counter % two == 0:
            return counter
        else:
            counter += min_inp

print "\nThis program takes two numbers and computes the LCM of them...\n"

first_number = input("Enter your first number: ")
second_number = input("Enter your second number: ")

print lcmCalculator(first_number, second_number)

---

哦，还有一件事。 Python 2.x 中的 input 将其输入计算为真正的 Python 代码。这意味着，使用不受控制的输入是危险的。

更好的方法是使用 raw_input然后使用 int 将输入显式转换为整数:

first_number = int(raw_input("Enter your first number: "))
second_number = int(raw_input("Enter your second number: "))