Question

首先，我只想说我最近开始编程，所以我不是很好。这是我的问题：

x = int(input("Write a number between 1-100: "))
while x > 100:
    x = int(input("The number must be less than 101: "))
while x < 1:
    x = int(input("The number must be higher than 0: "))
else:
    print ("The number is:",x)

有一种方法可以通过这样做来欺骗代码：

Write a number between 1-100: 101
The number must be less than 101: 0
The number must be higher than 0: 101
The number is: 101

我基本上不希望用户能够写出高于100或低于1的数字。

我很抱歉这个错误的解释，但我尽力了，再一次，我最近开始编程。

Answer 1

我会这样做：

x = int(input("Enter a number in the range [1, 100]: "))
while not (1 <= x <= 100):
    x = int(input("That number isn't in the range [1, 100]!: "))
else:
    print ("The number is:",x)

当然，您可以使用嵌套的if语句使您的提示更多地提供错误信息，如下所示：

x = int(input("Enter a number in the range [1, 100]: "))
while not (1 <= x <= 100):
    if x > 100:
        x = int(input("The number must be less than 101: "))
    else:
        x = int(input("The number must be greater than 0: "))
else:
    print ("The number is:",x)

请记住，您可以一次测试多个条件！

Answer 2

使用逻辑or来测试单个while中的条件：

while not 1 <= x <= 100:  
    x = int(input("The number must be in range [1, 100]: "))

这将迭代while循环，直到用户输入小于1或大于100的输入。您还可以注意到，如果用户继续输入无效输入，这将导致无限循环。我会让你弄清楚如何解决这个问题。

Answer 3

In Python, unlike other programming languages, expressions like a < b < c have the interpretation that is conventional in mathematics。这意味着您可以像这样编写while - 循环：

x = int(input("Write a number between 1-100: "))
while not 1 <= x <= 100:
    x = int(input("The number must be in the range 1-100: "))
else:
    print ("The number is:", x)

while条件循环不会自行保存

3 个答案: