Question

这样做之后如何让它循环回到开始？在每次交易之后，它结束并且不会返回以查看您是否可以选择其他选项。谢谢，非常感谢。

balance=7.52
print("Hi, Welcome to the Atm.")
print("no need for pin numbers, we already know who you are")
print("please selection one of the options given beneath")
print("""
    D = Deposit
    W = Withdrawal
    T = Transfer
    B = Balance check
    Q = Quick cash of 20$
    E = Exit
    Please select in the next line.   
""")
option=input("which option would you like?:")
if option==("D"):
    print("How much would you like to deposit?")
    amount=(int(input("amount:")))
    total=amount+balance
elif option ==("W"):
    print("How much would you like to withdrawl?")
    withdrawl=int(input("how much would you like to take out:?"))
    if balance<withdrawl:
        print("Error, insufficent funds")
        print("please try again")
elif option == "T":
    print("don't worry about the technicalities, we already know who you're          transferring to")
    transfer =int(input("How much would you like to transfer:?"))
    print("you now have", balance-transfer,"dollars in your bank")
elif option=="B":
    print("you currently have",balance,"dollars.")
elif option=="Q":
    print("processing transaction, please await approval")
    quicky=balance-20
    if balance<quicky:
         print("processing transaction, please await approval")
    print("Error, You're broke.:(")
elif option=="E":
      print("Thanks for checking with the Atm")
      print("press the enter key to exit")

Answer 1

好像你问的是一个sentinel value的循环。

在您打印菜单之前的某处，设置一个标记值：

keep_going = True

然后，最好在下一行（打印你想要在循环时看到的第一件事）之前，开始循环。

while keep_going:   # loop until keep_going == False

如上所述，这是一个无限循环。 while语句下面的缩进块中的所有内容都将按顺序重复。这显然不是我们想要的 - 我们必须有一些方法才能离开，这样我们就可以将我们的电脑用于其他事情了！这就是我们的哨兵进来的地方。

构建新菜单选项以允许用户退出。假设您将其键入＆＃34; Q＆＃34;，然后用户选择它。然后，在那个分支中：

elif option == 'Q':
    keep_going = False

由于那个分支中的所有内容都存在，我们＆＃34;脱落＆＃34;循环的底部，然后返回while语句，该语句现在无法检查。循环终止了！

顺便说一下，你应该考虑阅读The Python Style Guide。它非常易于阅读，让您了解如何使您的代码也易于阅读。大多数Python程序员都遵守它并期望其他人也这样做，所以你也应该这样做！如果您需要帮助来学习它，或者不确定您是否正确行事，则可以tools到check your code来帮助您保持清洁和无错误。

快乐的节目！

Python程序，如何制作一个atm程序循环

1 个答案: