当达到用户的数量目标时，我的程序如何停止运行？

Question

我的程序的目的是让用户输入捐赠目标。当达到这个数字目标时，我的程序应该停止。在向用户询问目标后，我的程序会询问捐赠金额，每个捐赠金额在达到目标之前相互相加。最后，在输入多个捐赠金额后，它应该加起来达到目标。

goal = ''
userDonation = ''
totalAmount = 0
userCashList = []
#asking for end goal
goal = int(input("Some Charity Donation Tracker... Please enter your goal: "))
print("Current Amount: ", totalAmount)
while totalAmount != goal:
userDonation = int(input("Please Enter Donation Amount: "))
print("Current Amount: ", userDonation + totalAmount)
userCashList.append(totalAmount)
for cash in userCashList:
totalAmount += userDonation
if userDonation == goal:
print("You have met your goal!")
else:
userCashList.append(userDonation)

输出：

Some Charity Donation Tracker... Please enter your goal: 100
Current Amount:  0
Please Enter Donation Amount: 200
Current Amount:  200
Please Enter Donation Amount: 300
Current Amount:  500
Please Enter Donation Amount: 200
Current Amount:  1300
Please Enter Donation Amount: 

我的捐款额在增加，但为什么不能停在100呢？

Answer 1

我不知道为什么您需要userCashList数组，而到目前为止您已经有了totalAmount来显示捐赠。不管怎样，我已经对你的代码做了几次更改，它似乎工作得很好！

首先，只有当totalAmount与goal不完全一样时，while totalAmount != goal才会运行。这意味着，如果你击中了目标，即用户捐赠了100，目标为100，代码只会通过while循环，而不会表明你已经通过了目标。

这是新代码：

goal = ''
userDonation = ''
totalAmount = 0
#asking for end goal
goal = int(input("Some Charity Donation Tracker... Please enter your goal: "))
print("Current Amount: ", totalAmount)
while True:
userDonation = int(input("Please Enter Donation Amount: "))
totalAmount = totalAmount + userDonation
print("Current Amount: ", totalAmount)
if totalAmount >= goal:
print("You have met your goal!")
break # Break out of the loop when the goal is met

while循环不是在总数不等于目标时才运行，而是永远运行。if语句会停止这一操作，如果总和等于或大于目标，则会检查每个增量。如果是，请通知用户并中断循环，从而停止脚本。

我刚开始回答SO问题，所以我希望这能有所帮助！：(

Answer 2

当条件为!=时，这意味着只有当total_amount等于目标时循环才会停止(如果total_amount大于目标(，而不是仅使用<(小于操作员(

您的代码，但有所改进：

total_amount = 0
# asking for end goal
goal = int(input("Some Charity Donation Tracker... Please enter your goal: "))
print("Current Amount:", total_amount)
while total_amount < goal:
user_donation = int(input("Please Enter Donation Amount:"))
total_amount += user_donation
print("Current Amount: ", total_amount)
else:
print("You have met your goal!")

Answer 3

我试图用较少的变量修改您的代码。请检查这是否是解决您问题的更好方法。

userDonation = ''
userCashList = []
#asking for end goal
goal = int(input("Some Charity Donation Tracker... Please enter your goal: "))
print("Current Amount: ", sum(userCashList))
while sum(userCashList) <= goal:
userDonation = int(input("Please Enter Donation Amount: "))
userCashList.append(userDonation)
print("Current Amount: ", sum(userCashList))
if sum(userCashList) >= goal:
print("You have met your goal!")
break

Answer 4

我在这里看到了几个问题：

错误的停车条件

你目前的条件是totalAmount != goal，但问题是要停止，你的totalAmount必须与既定目标完全相同，如果目标被totalAmount超过，但永远不会等于它，那么循环将永远不会停止。这就是为什么while循环中的停止条件应该是totalAmount < goal。

totalAmount的增量错误

在这个for循环中，您的总金额增加过多：

for cash in userCashList:
totalAmount += userDonation

这个for循环完全是不必要的，并且会影响应用程序的正确功能。

这就是我建议你的代码应该是：

goal = ''
userDonation = ''
totalAmount = 0
userCashList = []
#asking for end goal
goal = int(input("Some Charity Donation Tracker... Please enter your goal: "))
print("Current Amount: ", totalAmount)
while totalAmount < goal:
userDonation = int(input("Please Enter Donation Amount: "))
print("Current Amount: ", userDonation + totalAmount)
userCashList.append(userDonation)
totalAmount += userDonation
if totalAmount >= goal:
print("You have met your goal!")

正如您在这里看到的，没有必要使用break，因为循环条件是足够的。此外，我发现userCashList是捐款的某种记录。