Benjamin Dannhoff
513 PointsCode runs forever
The code ive written is verbatim that in the video. However, the loop runs on even after the tickets_remaining is at 0. Why?
TICKET_PRICE = 10
tickets_remaining = 100
while tickets_remaining: print("There are {} tickets_remaning.".format(tickets_remaining))
name = input("What is your name? ")
number_of_tickets = input(name + " how many tickets would you like to purchase? ")
number_of_tickets = int(number_of_tickets)
total = number_of_tickets * TICKET_PRICE
print("Your total is {}".format(total))
proceed = input("{}, would you like to proceed with your purchase? Yes or No? ".format(name))
if proceed == "yes":
print("SOLD!")
print("Thank you very much {}, please come back soon.".format(name))
print((tickets_remaining - number_of_tickets), "tickets are now remaning!")
else:
print("{}, thank you very much for your interest, please come back anytime.".format(name))
print("Sorry all sold out")
2 Answers
Maciej Badowski
1,842 PointsHi Benjamin, your code was running forever because (correct me if I'm wrong):
when you use
tickets_remaining - number_of_tickets
it deducts number of tickets, but does not update/save the amount in the variable tickets_remaining, meaning that every loop runs with the re-set amount of 100 tickets_remaining ... and so this will go endless.
when you use
tickets_remaining -= number_of_tickets
it is equal to
tickets_remaining = tickets_remaining - number_of_tickets
which basically is updating/re-writing the variable on the left, i.e. tickets_remaining with the result of the subtraction on the right (tickets_remaining - number_of_tickets) and as such decreases with every loop
not sure if I explained it enough but feel free to ask if unclear :)
KRIS NIKOLAISEN
Pro Student 52,004 PointsUsually if code runs forever there is a problem with a counter or condition. You have:
tickets_remaining - number_of_tickets
whereas if you check the video @4:20 the code is
tickets_remaining -= number_of_tickets
which would decrement tickets_remaining by tickets sold each loop through
Benjamin Dannhoff
513 PointsThank you very much, revising the code to -= worked. Do you know why it wouldn't work the way I had originally wrote it?
KRIS NIKOLAISEN
Pro Student 52,004 PointsKRIS NIKOLAISEN
Pro Student 52,004 PointsCan you post your code?