Python:在循环中对变量执行用户定义的加法

Question

这是我正在开发的大型“自动售货机”中的一个模块。不过，我遇到了一些问题。如果他们支付的金额不够($1.75)，他们将被要求输入额外的金额。我的部分问题是我不知道我应该做什么操作来改变循环内的赤字。我尝试过的所有事情都导致了错误，例如“预计输入最多 1 个参数，得到 3 个”等等。

selection = 5
loopCount = 0
deposit = 0
cost = 1.75
print("It costs $",cost,".")
deposit = float(input("Enter your money amount (e.g. 1.5 for $1.50, .50 for $0.50, etc.):\n--\n"))
deficit = cost - deposit
change = deposit - cost
if deposit < cost:
    while deficit > 0 and loopCount < 1:
        ??? = float(input("Please enter an additional $",deficit,"."))
        loopCount += 1
if deposit >= cost:
    print("Thank you for purchasing item#",selection,". Your change is $",change,".")

Answer 1

这对我有用。请确保增加 loopCount，因为现在它不会循环多次。

selection = 5
loopCount = 0
deposit = 0
cost = 1.75
print("It costs $",cost,".")
deposit = float(input("Enter your money amount (e.g. 1.5 for $1.50, .50 for $0.50, etc.):\n--\n"))
deficit = cost - deposit
change = deposit - cost
if deposit < cost:
    while deficit > 0 and loopCount < 1:
        deficit -= float(input("Please enter an additional ${}.".format(deficit)))
        loopCount += 1
if deposit >= cost:
    print("Thank you for purchasing item#",selection,". Your change is $",change,".")