Question

我有一段时间是真的，所以如果飞机上没有足够的座位你就不能预订航班，但我想回到前一行代码（第8行），因为当我这样做的时候：

# b means bookings, fn means Flight Number
b = 0
maxpass = 68
minpass = 0
fn = "FNO123"
amount = 0
seatsremain = 68 - b

print ("Welcome to Flight Booking Program")

print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
flight = input()

while flight != "X":
    seatsremain = 68 - b

    while True:
        if flight == fn:
            print ("There are currently", seatsremain, "seats remaining")
            break
        else:
            print ("ERROR")
            print ("Not a valid flight number! Remember input is CASE SENSITIVE")
            print ("Welcome to Flight Booking Program")
            print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
            flight = input()

    print ("Would you like to book or cancel your flight?")
    booking = input().lower()        

    while True:
        if b == maxpass and booking == "b" or booking == "book":
            print ("Sorry but the flight you want is currently fully booked. Sorry for Inconviniance")

            print ("Welcome to Flight Booking Program")
            print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
            flight = input() 


        else:
            break

    if booking == "c" or booking == "b" or booking == "book" or booking == "cancel":
        if booking == "b" or booking == "book":
            print ("How many seats are you booking?")
            while True:
                try:
                    amount = int(input())
                    if amount <1 or amount >seatsremain:
                        print ("ERROR")
                        print ("You must book at least 1 seat and not exceed the maximum amount of seats avaliable")
                        print ("There are currently", seatsremain, "seats remaining")
                        print ("How many seats are you booking?")
                    else:
                        b = b + amount
                        print ("Your flight has been Booked!")
                        print ("Welcome to Flight Booking Program")
                        print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
                        flight = input()
                        break
                except ValueError:
                    print ("You must enter a valid number!")

        else:
            if booking == "c" or booking == "cancel":
                print ("How many seats are you canceling?")
                while True:
                    try:
                        amount = int(input())
                        if amount <1 or amount >b:
                            print ("ERROR")
                            print ("You must cancel at least 1 seat and not exceed the minimum amount of seats avaliable")
                            print ("There are currently", seatsremain, "seats remaining")
                            print ("How many seats are you cancelling?")
                        else:
                            b = b - amount
                            print ("Your flight has been Cancelled!")
                            print ("Welcome to Flight Booking Program")
                            print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
                            flight = input()
                            break
                    except ValueError:
                        print ("You must enter a valid number!")
    else:
        print ("Error")
        print ("Please only type book or cancel")


print("There are", b, "people booked on flight", fn)

不断重复。

以下是代码的其余部分：

{{1}}

Answer 1

你所要求的并不是100％清楚，但我怀疑你想要这样的东西：

class MyOwnError(Exception):
    def __init__(self, message):
        self.message = message
    def __str__(self):
        return repr(self.message)

while flight != "X":
    try:
        seatsremain = 68 - b


        if flight == fn:
            print ("There are currently", seatsremain, "seats remaining")
        else:
            raise MyOwnError("Not a valid flight number!")

        # etc...
                    if amount <1 or amount >b:
                        print ("ERROR")
                        print ("You must cancel at least 1 seat and not exceed the minimum amount of seats avaliable")
                        print ("There are currently", seatsremain, "seats remaining")
                        print ("How many seats are you cancelling?")
                    else:
                        b = b - amount
                        raise MyOwnError("Your flight has been Cancelled!")
        # etc...

    except MyOwnError as e:
        print (e.message)
        print ("Welcome to Flight Booking Program")
        print ("Please enter the flight number you want to book/cancel with? (Case Sensitve)")
        flight = input()

这里异常强制跳出所有循环，并可以重新提示输入。您可以通过使用嵌套的try / except语句来扩展此想法以处理座位取消循环。

运行上一行？

1 个答案: