while 循环无法正常工作，我需要使用其他东西吗？

Question

I need to get the size of a pizza, and return it. I am using a while loop (not sure if I need to use something else?) and the problem is, even when I enter a valid choice, it prompts me to enter the size again instead of returning the size.

def pizzaSize():
   print("What size of pizza do you want\n (s)mall, (m)edium, or (l)arge?\n")
   size = input()
   while size != 'l' and size != 'm' and size != 's':
      print("ERROR invalid pizza size")
      size = input()
   return size`

I am pretty new to this, just started my first programming class.

Edit:

I believe what is causing my issue is another piece of the code. I was calling the function multiple times and causing it to repeat. Now I have a separate issue. How do I take what is returned from a previous function and use it in a later one without calling the previous function?

def pizzaPrice():
if size == "s":
    cost = 9 + .50 * numTop
elif size == "m":
    cost = 11 + .75 * numTop
elif size == "l":
    cost = 13 + 1 * numTop
return cost

numTop is what is returned in a previous function. How do I get that in the pizzaPrice function? It says it is not defined, but when I define it as the function, it calls that function.

Answer 1

Your code seemed to run fine for me. It might be overkill but you can try to the following code. I am pretty new to programming too, but I have seen other people use True and False when using while loops. I hope this helps! Best of luck!!

**EDIT I saw that you posted an additional question so I hope that this helps too. I am not sure how you are getting the "numtop" numbers but if its through a input() like the pizza size then be sure to specify it as a float since you will be using it with multiplication (inputs default as strings). In the pizzaPrice() function you need to specify that the size and numtop variables are the results of the numbofTops() and pizzaSize() functions.

def numbofTops():


     numTop = float(input("how many toppings? "))
     return (numTop)


def pizzaSize():
    validAnswer = False
    print("What size of pizza do you want\n (s)mall, (m)edium, or (l)arge?\n")
    size = input("What size of pizza do you want\n (s)mall, (m)edium, or (l)arge?\n")

    while not validAnswer:
        if size != 'l' and size != 'm' and size != 's':
            print("ERROR invalid pizza size ")
            size = input()
        else:
            validAnswer = True

            return size


def pizzaPrice():
    numTop = numbofTops()
    size = pizzaSize()

    if size == "s":
        cost = 9 + .50 * numTop
        print(cost)

    elif size  == "m":
        cost = 11 + .75 * numTop
        print(cost)

    elif size  == "l":
        cost = 13 + 1 * numTop
        print(cost)
    return cost


pizzaPrice()