我有一些代码没有做我想要的，但我没有收到错误消息

Question

I'm doing my 20-hour coding assignment for my GCSE and I'm trying to come up with some python code to take a food order, then add up totals and return a running total for all orders until that point. There's a couple of problems with my current code and I'm not getting an error message so I'm not sure how to fix it to make it do what I want.

Here's my code: python code for ordering system

The first problem is that something is going wrong when certain combinations of item references are inputted. The totals are not adding as they should, giving me a float with an unreasonable amount of decimal places yet this isn't always the case. The other problem is that when I enter Y to place another order, it doesn't let me. Though when I enter N to stop ordering, it does what I want it to.

Here's the output demonstrating these problems: code that's gone wild with the adding and not allowing me to enter another order

Here's the output where everything seems ok: all good

I've managed to implement these two separate concepts, the Y/N to stop or proceed and the ordering code, in other bits of code yet when I try them here, it's not working. We've been looking over it for ages and still can't figure out what is going on. Any help would be appreciated!

[edit] here's the code that I'm struggling with:

>menuItems = [' ', 'Large all day breakfast', 'Small all day breakfast', 'Hot dog', 'Burger', 'Cheese burger', 'Chicken goujons', 'Fries', 'Salad', 'Milkshake', 'Soft drink', 'Still water', 'Sparkling water']
>menuPrices = [0.00, 5.50, 3.50, 3.00, 4.00, 4.25, 3.50, 1.75, 2.20, 2.20, 1.30, 0.90, 0.90]
>orderTotal = 0 #resets the order total so that the total is accurate
>runningTotal = float(0.0)
>orderWords = 'Order: '
>orderItem = 1
>ordering = True
>while ordering == True:
>    while orderItem != 0:
>       orderItem = int(input('Please list the item reference number: '))
>       orderTotal = orderTotal + (menuPrices[orderItem])
>       orderWords = orderWords + ' ' + (menuItems[orderItem])
>       runningTotal = runningTotal + (menuPrices[orderItem])
>   else:
>       print(orderWords)
>       print('Your total is: £', orderTotal)
>       ordering = False
>else:
>   proceed = str(input('Do you want to place another order (Y/N)? '))
>   if proceed == 'Y':
>       ordering = True
>   if proceed == 'N':
>       ordering = False
>       print('Running total: £', runningTotal)
>   else:
>       ordering = True

Answer 1

As @quaabaam said, please copy and paste the problematic code in the question, that way we can copy it if we need to and can then debug it.

I'm assuming the menuItems and menuPrices are supposed to be linked, meaning that "Large all day breakfast" costs 5.50. In that case it would be best to use dictionaries. for example:

Menu = {"Large all day breakfast" : 5.50, "Small all day breakfast" : 3.50, ... }

This way, to get a price you just have to call, for example x = Menu["Large all day breakfast"] the price to x, in this case 5.50.

Also, you might want to change your while ordering == True into a function, for example

def ordering():
    while True:
        orderItem = int(input(...
        if orderItem != 0:
            orderTotal += menuPrices[orderItem] #x += 1 means that you increase x by 1, it's basically what you wrote but different notation
        else:
            print(orderWords)
        ...
            break
    proceed(runningTotal)


def proceed(runningTotal):
    proceed = ...
    elif proceed == "N":
        ordering()

If you haven't yet looked into functions, I would highly suggest it since it is very vital, especially here