如何将sellProduct方法应用于菜单中的每个选项?

Question

我不明白为什么我不能将processSale方法连接到sellProduct方法。我认为类和其他方法不需要任何更改，因为我只是遵循了给我的标准。

#candy machine
class CashRegister:
def __init__(self, cashOnHand = 500,):
if cashOnHand < 0:
self.cashOnHand = 500
else:
self.cashOnHand = cashOnHand
def currentBalance(self):
return self.cashOnHand
def acceptAmount(self, cashIn):
self.cashOnHand += cashIn
class Dispenser:
def __init__(self, numberOfItems = 50, productCost = 50):
if numberOfItems < 0:
self.numberOfItems = 50
else:
self.numberOfItems = numberOfItems
if productCost < 0:
self.productCost = 50
else:
self.productCost = productCost

def getCount(self):
return self.numberOfItems
def getProductCost(self):
return self.productCost
def makeSale(self):
self.numberOfItems -= 1
class MainProgram:
def showMenu(self):
global userInput
print("**** Welcome to Eros' Candy Shop ****")
print("To select an item enter")
print("""1 for Candy
2 for Chips
3 for Gum
4 for Cookies
0 to View Balance
9 to Exit""")
userInput = int(input("Enter your choice: "))
def sellProduct(self, useDispenser = Dispenser(), useRegister = CashRegister()):
try:
self.useDispenser = useDispenser
self.useRegister = useRegister
if self.useDispenser.getCount != 0:
print(f"It costs {self.useDispenser.getProductCost} cents")
cash = int(input("Please enter your payment: "))
change = cash - self.useDispenser.getProductCost
if change < 0:
print("Insufficient money!")
print(f"You need {self.useDispenser.getProductCost - cash} cents more")
return
else:
print(f"Your change is {change} cents")
self.useRegister.acceptAmount(self.useDispenser.getProductCost)
self.useDispenser.makeSale
return
elif self.useDispenser.getCount == 0:
print("The product you chose is sold out! Try the other itmes")
return
except ValueError:
print("You entered an incorrect value. Please use the numbers on the menu only")
def processSale(self):
Register = CashRegister()
Candy = Dispenser()
Chips = Dispenser()
Gum = Dispenser()
Cookies = Dispenser()
while True:
self.showMenu
if userInput == 1:
self.sellProduct(Candy, Register)
elif userInput == 2:
self.sellProduct(Chips, Register)
elif userInput == 3:
self.sellProduct(Gum, Register)
elif userInput == 4:
self.sellProduct(Cookies, Register)
elif userInput == 0:
print("Current Balance is" + str(Register.currentBalance))
elif userInput == 9:
break
mainProgram = MainProgram()
mainProgram.showMenu()

如何在userInput 1-4上使用sellProduct方法?当应用类的属性以及如何连接它们时，我感到困惑。你能指出我犯了什么错误，我还能做些什么改进吗?

Answer 1

这里有一些你可以改进的地方:

1. 当你调用你的方法时，不要忘记括号:

self.useDispenser.getCount()
self.useDispenser.getProductCost()

2. 创建一个无限循环，连续请求showMenu内的输入，并删除processSale内的输入(例如):

def showMenu(self):
global userInput 
userInput = 0
print("**** Welcome to Eros' Candy Shop ****")
while userInput != 9:
print("To select an item enter")
print(MENU)
userInput = int(input("Enter your choice: "))

if userInput < 9:
self.processSale()

但是请相应地更新整个程序。

希望有帮助!