Programming

class CashRegister(object):
    """A class that makes big money."""
    def __init__(self, twenties, tens, fives, ones):
        self.twenties = twenties
        self.tens = tens
        self.fives = fives
        self.ones = ones

    def description(self):
        print "I have %s twenties, %s tens and I have %s fives." % (self.twenties, self.tens, self.fives)

    def is_broke(self):
        if self.ones:
            print "Yep! I'm flush.\n"

        else:
            print "Please help me! I am broke.\n"

Yesterday = CashRegister(4, 8, 16, 1)
Yesterday.description()
Yesterday.is_broke()

Today = CashRegister(5, 10, 20, False)
Today.description()
Today.is_broke()

class CashRegister(object):
    def __init__(self, drawer):
        self.drawer = self.formatMoney(drawer)
    ## Purchase function
    def purchase(self, price, amount_tendered):
        change_required = self.sumMoney(self.formatMoney(amount_tendered)) - price
        if change_required == 0:
            return [0, 0, 0, 0]
        if change_required > self.sumMoney(self.drawer):
            return 3
        if self.sumMoney(self.formatMoney(amount_tendered)) < price:
            return 2
        ret = {'ones': 0, 'fives': 0, 'tens': 0, 'twenties': 0}
        if change_required >= 20:
            ret['twenties'] = change_required / 20
            change_required = change_required % 20
        if change_required >= 10:
            ret['tens'] = change_required / 10
            change_required = change_required % 10
        if change_required >= 5:
            ret['fives'] = change_required / 5
            change_required = change_required % 5
        ret['ones'] = change_required
        return ret
    ## Helper function
    def sumMoney(self, l):
        s = 0
        s += l['ones']
        s += l['fives'] * 5
        s += l['tens'] * 10
        s += l['twenties'] * 20
        return s
    def formatMoney(self, l):
        return {'ones': l[0], 'fives': l[1], 'tens': l[2], 'twenties': l[3]}

def sumMoney(self, l):
        s = 0
        s += l['ones']
        s += l['fives'] * 5
        s += l['tens'] * 10
        s += l['twenties'] * 20
        return s

# You dont want function calls in __init__ because the functions haven't been
# initialized yet.  Use __init__ to assign values and such
# from the arguments you provide when you create an instance of the class.
class CashRegister(object):
    def __init__(self, ones, fives, tens, twenties):
        self.drawer = {'ones': ones, 'fives': fives, 'tens': tens, 'twenties': twenties}
        self.tender = {'ones': 0, 'fives': 0, 'tens': 0, 'twenties': 0}
        self.cash = {'ones': 0, 'fives': 0, 'tens': 0, 'twenties': 0}


## Purchase function
    def purchase(self, price, ones, fives, tens, twenties):
        self.tender = {'ones': ones, 'fives': fives, 'tens': tens, 'twenties': twenties}
        change_required = self.sum_tendered() - price

        if change_required == 0:
            return "err0" # distinguish error numbers from dollars

        if self.sum_tendered() < price:
            return "err2"

        # if change_required > self.sumMoney(self.drawer):
        if change_required > self.sum_drawer():
            return "err3"

        return change_required
 
## Helper functions
    def formatMoney(self, amount):
        self.cash = {'ones': 0, 'fives': 0, 'tens': 0, 'twenties': 0}
        if amount >= 20:
            self.cash['twenties'] = amount / 20
            amount = amount % 20

        if amount >= 10:
            self.cash['tens'] = amount / 10
            amount = amount % 10

        if amount >= 5:
            self.cash['fives'] = amount / 5
            amount = amount % 5
        self.cash['ones'] = amount

        return self.cash

    def sumMoney(self, fmt):
        self.cash = fmt
        s = 0
        s += self.cash['ones']
        s += self.cash['fives'] * 5
        s += self.cash['tens'] * 10
        s += self.cash['twenties'] * 20
        return s

    def cash_drawer(self):
        return self.drawer
    def cash_tendered(self):
        return self.tender
    def sum_drawer(self):
        return self.sumMoney(self.drawer)
    def sum_tendered(self):
        return self.sumMoney(self.tender)

############
# some random testing
############

d1 = {}
reg = CashRegister(20, 20, 10, 10)

change = reg.purchase(38, 0, 0, 0, 2)
d1 = reg.cash_tendered()
tender = reg.sum_tendered()
print 'tendered:$%s = %s, %s, %s, %s' % (tender, d1['ones'], d1['fives'], d1['tens'], d1['twenties'])
d1 = reg.formatMoney(change)
print 'change:$%s = %s, %s, %s, %s' % (change, d1['ones'], d1['fives'], d1['tens'], d1['twenties'])
d1 = reg.cash_drawer()
drawer = reg.sum_drawer()
print 'drawer:$%s = %s, %s, %s, %s' % (drawer, d1['ones'], d1['fives'], d1['tens'], d1['twenties'])