解决程序的“全局”问题？

问题描述

最初，我在存款和取款功能中包含“全局”语句。 教授告诉我，我不能使用全局语句来完成这项作业。 Codio在顶部创建了一个变量，我无法移动它。 我必须在我的函数中访问该变量。 现在，我需要让我的函数返回，以使“ account_balance”变量在每次取款和存款后都会更新。 当前，该代码功能大部分还可以，但是在每次进行货币操作后，我都会为余额函数输入“ b”，并且先前的操作将被清除，而我又恢复了默认余额。 我在这里做错了什么？ 代码如下：

    import sys

#account balance 
account_balance = float(500.25)


#<--------functions go here-------------------->
#printbalance function
def balance():
  print('Your current balance:\n%.2f' % account_balance)


#deposit function
def deposit(temp):
  deposit_amount = float(input('How much would you like to deposit today?\n'))
  temp = temp + deposit_amount
  print('Deposit was $%.2f, current balance is  $%.2f' % (deposit_amount, temp))
  return temp

#withdraw function
def withdraw(temp2):

  withdrawal_amount = float(input('How much would you like to withdraw today?\n'))
  if withdrawal_amount > temp2:
    print('$%.2f is greater than your account balance of $%.2f ' % (withdrawal_amount, temp2))
  else:
    temp2 -= withdrawal_amount
    account_balance = temp2
    print('Withdrawal amount was $%.2f, current balance is $%.2f' % (withdrawal_amount, temp2))
    return temp2

#User Input goes here, use if/else conditional statement to call function based on user input

userchoice = ''

while userchoice!= 'Q':
  userchoice = input('What would you like to do?\n(B)alance?, (W)ithdraw?, (D)eposit?, (Q)uit?\n')
  userchoice = userchoice.upper()

  if (userchoice == 'B'):
    balance ()
  elif userchoice == 'W':
    withdraw (account_balance)
  elif userchoice == 'D':
    deposit (account_balance)
  elif userchoice == 'Q':
    print('Thank you for banking with us.')
    break

由于不允许使用全局变量，因此您需要使用由存款和取款函数返回的变量。

while userchoice!= 'Q':
userchoice = input('What would you like to do?\n(B)alance?, (W)ithdraw?, (D)eposit?, (Q)uit?\n')
userchoice = userchoice.upper()

if (userchoice == 'B'):
  balance ()
elif userchoice == 'W':
    new_balance = withdraw(account_balance)
    if new_balance:
        account_balance = new_balance
elif userchoice == 'D':
    account_balance = deposit (account_balance)
elif userchoice == 'Q':
    print('Thank you for banking with us.')
    break

提款功能要么返回新的帐户余额，要么打印出您的帐户中没有足够的钱。 调用withdraw函数（）后，检查它是否返回了任何东西。 如果是这样，您将使用存储在new_balance中的返回值更新account_balance。

对于存款功能，您只需要使用该功能返回的值来更新account_balance。