[Solved] Answer Error, Only outputting Zero

Question

How to debug your (small) program

Okay so let’s start from the top and go line-by-line. There’s a lot of issues here.

aLimit=300
bLimit=500
cLimit=100
aPrice=20
bPrice=15
cPrice=10
ticketSold=1
totalIncome=0

These are all globals since you defined them in the module scope. That’s a Bad Thing. Don’t do it. If they’re constants, use CAPS to mention that, but they should still not be global.

def Main(): # I mentioned in my comment, but Capitals are classes
            # by convention, use def main() instead
    getTickets(aLimit)

Let’s stop and look at getTickets() so we can follow execution

def getTickets(limit): # camelCase is not advised per PEP8, but it's still around
                       # so I wouldn't worry about this one so much as Capitalized
    ticketSold=int(input("How many tickets were sold? "))
    # perfect implementation, though be prepared for users who
    # will type forty instead of 40!
    if (ticketsValid(ticketSold,limit)==True):
        return ticketSold
    # so any time you write `if ___ == True`, stop and realize that the compare
    # is unnecessary. if ticketsValid(ticketSold,limit) works just as well!
    else:
        getTickets(limit)
    # wha-? If the tickets aren't valid, we're RECURSING??! This is an infinite loop.
    # are you doing this to prompt for more input if tickets aren't valid? That's Bad

Okay so you invoked ticketsValid in there, so let’s look there now…

def ticketsValid(Sold,limit): # another Capital here!
    while Sold > limit or Sold < 0: # this should be an if??
        print ("...")
        return False
    return True
# Since you have a set amount, this is MUCH easier written as:
## def ticketsValid(sold,limit):
##     return 0 < sold < limit
# but should this be <=?

Alright, back to main–ahem–Main….

def Main():
    ...
    sectionIncome = calcIncome(ticketSold,aPrice)

And hop back to calcIncome

def calcIncome(ticketSold,price):
    return ticketSold*price # why not just substitute this???

Main again

def Main():
    ...
    sectionIncome += totalIncome
    # this sets sectionIncome equal to the current value of sectionIncome
    # plus the current value of totalIncome, which is currently zero.

Then basically the whole thing gets repeated down the function. There’s your issue, the += adds zero to sectionIncome instead of adding sectionIncome to totalIncome!

The better way to do this!

Here’s the problem. You’re trying to use functional programming to do object-oriented tasks. Most of these kind of issues are when new programmers who are interested in video games think that the best task to learn programming is a text adventure. Unfortunately, the best languages for text adventures (those that easily implement a Finite State Machine) are not usually those that beginners start with, so it’s hard to implement WELL!

In your case, you should be creating objects to do the workload for you. Python does this elegantly, but it’s rarely in beginning tutorials. As an example, I wrote out a bit that does exactly what you did (defines three sections of seating in a theater and sells one ticket per section)

class Section(object):
    def __init__(self,price,limit):
        self.price = price
        self.tickets_sold = 0
        self.limit = limit
    @property
    def sales(self):
        return self.price*self.tickets_sold
    def sell(self,qty=1):
        if not isinstance(qty,int): raise TypeError("Must sell an int of tickets")
        if qty < 1: raise ValueError("Must sell positive tickets")
        qty = min(qty,self.limit-self.tickets_sold)
        self.tickets_sold += qty
        # optional print statement for the user

class Theater(object):
    def __init__(self,sections):
        self.sections = sections
    @property
    def sales(self):
        return sum(section.sales for section in self.sections)

theater = Theater([Section(20,300),
                  Section(15,500),
                  Section(10,100)])

for section in theater.sections:
    section.sell(1)
print(theater.sales)

The big problem with this is just that you don’t know how to do it. Creating an object that will stay constant, then throw several instances of it around with specific attributes is precisely the approach I would favor in this circumstance.

Accepted Answer