ATM algorithm

[boomtifier]

I have my instructions in the top of my code. But for some reason when I input a decimal and then return my error message like it is supposed to then I input a valid amount it prints everything twice, once for the valid input then once for the valid input here is what i am getting(below bottom).

01
"""
02
withdraw_money()
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a.  prompt user for a money amount in US Dollars (no cents, i.e. no
04
    fractional part allowed)
05
b.  print a preamble which says that user will see the breakdown of the
06
    money in banknotes
07
c.  print maximum number of $100 bills that can be given for the amount
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    given by user
09
d.  print maximum number of $50 bills that can be given for the amount left
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    over from previous step
11
e.  print maximum number of $20 bills that can be given for the amount left
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    over from previous step
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f.  print maximum number of $10 bills that can be given for the amount left
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    over from previous step
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g.  print maximum number of $5 bills that can be given for the amount left
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    over from previous step
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h.  print maximum number of $2 bills that can be given for the amount
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    left over from previous step
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i.  print maximum number of $1 bills that can be given for the amount left
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    over from previous step
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"""
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import math
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import string
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def withdraw_money():
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    withdraw = 0
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    hundreds = 0
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    fifty = 0
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    twenty = 0
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    ten = 0
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    five = 0
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    two = 0
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    one = 0
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    withdraw = input("Input the amount you would like to withdraw\n--> ")
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    while withdraw >= 100:
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        hundreds += 1
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        withdraw -= 100
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    while withdraw >= 50:
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        fifty += 1
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        withdraw -= 50
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    while withdraw >= 20:
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        twenty += 1
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        withdraw -= 20
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    while withdraw >= 10:
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        ten += 1
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        withdraw -= 10
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    while withdraw >= 5:
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        five += 1
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        withdraw -= 5
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    while withdraw >= 2:
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        two += 1
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        withdraw -= 2
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    while withdraw >= 1:
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        one += 1
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        withdraw -= 1
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    if withdraw < 1 and withdraw > 0:
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        print "invalid input"
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        print "do not insert a decimal"
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        withdraw_money()
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    print "Here is the bill breakdown for the amount input"
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    print hundreds, "number of 100s"
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    print fifty, "number of 50s"
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    print twenty, "number of 20s"
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    print ten, "number of 10s"
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    print five, "number of 5s"
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    print two, "number of 2s"
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    print one, "number of 1s"

and what it is giving me

01
>>>
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Input the amount you would like to withdraw
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--> 200.30
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invalid input
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do not insert a decimal
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Input the amount you would like to withdraw
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--> 253
08
Here is the bill breakdown for the amount input
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2 number of 100s
10
1 number of 50s
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0 number of 20s
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0 number of 10s
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0 number of 5s
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1 number of 2s
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1 number of 1s
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Here is the bill breakdown for the amount input
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2 number of 100s
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0 number of 50s
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0 number of 20s
20
0 number of 10s
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0 number of 5s
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0 number of 2s
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0 number of 1s

[Ancient Dragon]

What language did you write the program in? You need to post the code you have written -- what you posted is ok, but doesn't help anyone to determine the cause of the problem.

[JasonHippy]

That looks a lot like Python code to me. I think the OP has misposted in the C section.

To compound things, he seems to have a load of line numbers included in the code he posted. I've just cleaned it up.
Here's the OPs original python code:

"""
withdraw_money()
a.  prompt user for a money amount in US Dollars (no cents, i.e. no
    fractional part allowed)
b.  print a preamble which says that user will see the breakdown of the
    money in banknotes
c.  print maximum number of $100 bills that can be given for the amount
    given by user
d.  print maximum number of $50 bills that can be given for the amount left
    over from previous step
e.  print maximum number of $20 bills that can be given for the amount left
    over from previous step
f.  print maximum number of $10 bills that can be given for the amount left
    over from previous step
g.  print maximum number of $5 bills that can be given for the amount left
    over from previous step
h.  print maximum number of $2 bills that can be given for the amount
    left over from previous step
i.  print maximum number of $1 bills that can be given for the amount left
    over from previous step
"""
import math
import string

def withdraw_money():
    withdraw = 0
    hundreds = 0
    fifty = 0
    twenty = 0
    ten = 0
    five = 0
    two = 0
    one = 0
    withdraw = input("Input the amount you would like to withdraw\n--> ")
    while withdraw >= 100:
        hundreds += 1
        withdraw -= 100
    while withdraw >= 50:
        fifty += 1
        withdraw -= 50
    while withdraw >= 20:
        twenty += 1
        withdraw -= 20
    while withdraw >= 10:
        ten += 1
        withdraw -= 10
    while withdraw >= 5:
        five += 1
        withdraw -= 5
    while withdraw >= 2:
        two += 1
        withdraw -= 2
    while withdraw >= 1:
        one += 1
        withdraw -= 1
    if withdraw < 1 and withdraw > 0:
        print "invalid input"
        print "do not insert a decimal"
        withdraw_money()

    print "Here is the bill breakdown for the amount input"
    print hundreds, "number of 100s"
    print fifty, "number of 50s"
    print twenty, "number of 20s"
    print ten, "number of 10s"
    print five, "number of 5s"
    print two, "number of 2s"
    print one, "number of 1s"

@boomtifier :
The reason you are getting your output twice is because you are recursively calling the function.

So what is happening is:
The first time through the function, you enter an invalid decimal value. Because of the remainder at the end of the note counting operation, you are displaying an error message and making a recursive call to the withdraw_money function.

The second time through the function, you enter a valid integer value, or a decimal ending in .00. Your note counting code counts the notes, there is no remainder and it prints the notes that you get. The 2nd function call then returns us, bringing us to the end of the first function call where the results from the first value are being displayed.

So with your existing code, if you entered n invalid values and 1 valid value, you would get n+1 results printed!

Your best bet would be to set up a loop and loop until you got a valid value from the user. The simplest modification to your function would be:

def withdraw_money():
    valid = False   # The user is always guilty until proven innocent! ;)

    while not valid: # loop until we get something valid from the user
        # initialise all counters to 0
        withdraw = 0
        hundreds = 0
        fifty = 0
        twenty = 0
        ten = 0
        five = 0
        two = 0
        one = 0

        # Get user input
        withdraw = input("Input the amount you would like to withdraw\n--> ")

        # Determine the quantities of each note denomination
        while withdraw >= 100:
            hundreds += 1
            withdraw -= 100
        while withdraw >= 50:
            fifty += 1
            withdraw -= 50
        while withdraw >= 20:
            twenty += 1
            withdraw -= 20
        while withdraw >= 10:
            ten += 1
            withdraw -= 10
        while withdraw >= 5:
            five += 1
            withdraw -= 5
        while withdraw >= 2:
            two += 1
            withdraw -= 2
        while withdraw >= 1:
            one += 1
            withdraw -= 1

        # If there is a remainder output an error message
        if withdraw < 1 and withdraw > 0:
            print "invalid input"
            print "do not insert a decimal"
        else: # the user entered a valid value
            valid = True

    # If we get here we know the user entered a valid value,
    # so we can output their results!
    print "Here is the bill breakdown for the amount input"
    print hundreds, "number of 100s"
    print fifty, "number of 50s"
    print twenty, "number of 20s"
    print ten, "number of 10s"
    print five, "number of 5s"
    print two, "number of 2s"
    print one, "number of 1s"

[TrustyTony]

I would prefer to go with more general approach, and definately not use the dangerous input in Python 2:

def withdraw_money():
    denoms = (100, 50, 20, 10, 5, 2, 1)
    while True:
        try:
            withdraw = int(raw_input('amount of money: '))
            break
        except Exception as e:
            print('Incorrect input: %s' % e)


    # If we get here we know the user entered a valid value,
    # so we can output their results!
    print("Here is the bill breakdown for the amount input")
    for d in denoms:
        count = withdraw // d
        print('%i x $%i' % (count, d))
        withdraw -= count * d

withdraw_money()

[boomtifier]

Sorry for the late reply i was in a coma, Thanks anyway.