请审查我的示例Python程序代码

Question

我正在学习Python，因为我想把这门语言的基本概念教给11岁的孩子们（我是一名老师）。我们已经做了一些基础的工作，让他们理解编程的基本要素，以及如何把任务拆分成小块等等。Python是英国新课程中将要教授的语言，我不想让孩子们养成坏习惯。下面是我写的一个小程序，没错，我知道它写得不好，但如果能给我一些改进的建议，我会非常感激。

我还在努力学习这门语言的教程，所以请多多包涵！:o)

# This sets the condition of x for later use
x=0
# This is the main part of the program
def numtest():
    print ("I am the multiplication machine")
    print ("I can do amazing things!")
    c = input ("Give me a number, a really big number!")
    c=float(c)
    print ("The number", int(c), "multiplied by itself equals",(int(c*c)))
    print("I am Python 3. I am really cool at maths!")
    if (c*c)>10000:
        print ("Wow, you really did give me a big number!")
    else:
         print ("The number you gave me was a bit small though. I like bigger stuff than that!")

# This is the part of the program that causes it to run over and over again.
while x==0:
    numtest()
    again=input("Run again? y/n >>>")
    if x=="y":
        print("")
        numtest()
    else:
        print("Goodbye")

Answer 1

你需要结束这个循环。

你的 while 循环应该是：

while again == 'y':

这样的话，

again = 'y'


def numtest():
    print ("I am the multiplication machine")
    print ("I can do amazing things!")
    c = input("Give me a number, a really big number!")
    c = float(c)
    print ("The number", int(c), "multiplied by itself equals", (int(c * c)))
    print("I am Python 3. I am really cool at maths!")
    if (c * c) > 10000:
        print ("Wow, you really did give me a big number!")
    else:
        print ("The number you gave me was a bit small though. I like bigger stuff than that!")

# This is the part of the program that causes it to run over and over again.
while again == 'y':
    numtest()
    again = input("Run again? y/n >>>")
    if again != "y":
        print("Goodbye")

Answer 2

既然你想教大家好的编程风格：

1. 不要用像 x 这样的变量名，除非你是在画图。可以参考 PEP008 来了解命名规则和风格。

2. 保持空格的一致性：

   c = input ("Give me a number, a really big number!")
   
   c=float(c)
   

这样是不一致的。哪种写法更好呢？

如果你真的想要一个无限循环的话：

    while True:
        numtest()

        again = input("Run again? y/n >>>")

        if again.lower().startswith("n"):
            print("Goodbye")
            break

不过，有些人认为使用 break 是不好的风格，你同意吗？你会怎么重写这个循环，让它不使用 break 呢？这或许可以作为你学生的一个练习？

Answer 3

你似乎不需要这个变量 x

while True:
    numtest()
    again = input("Run again? y/n >>>")
    if again == "y":       # test "again", not "x"
        print("")
    else:
        print("Goodbye")
        break              # This will exit the while loop