Question

Keep in mind that I am still very new to python coding as I am only just into chapter 5 of my python coding class. Keeping that in mind, I am attempting to create a sum calculator using a “while loop” to continue until the user enters a negative number instead of a positive number.

In case I am not entirely clear in my description of my question I will post the exact homework problem here:

Chapter 5, page 200, #8
Sum of Numbers

Write a program with a while loop that asks the user to enter a series of positive numbers. The user should enter a negative number to signal the end of the series. After all the positive numbers have been entered, the program should display their sum.

Now for the code that I have written so far:

def main():
    number = float(input('Please enter in a positive number: '))
    while number > 0:
        positiveNumber()
    while number < 0:
        calculateTotal()
        printTotal()

def positiveNumber():
    number = float(input('If you are finished please enter a negative number.' + \ 'Otherwise, enter another positive number: '))
    while number > 0:
        positiveNumber()
    while number < 0:
        calculateTotal()
        printTotal()

def calculateTotal():
    total = 0 + number

def printTotal():
    print('The sum of your numbers is: ', total)

main()

• In line 11, I have the “+ \” sign there because I wanted to make an enter space there in order to have a cleaner looking text, but that does not seem to work.

I apologize if this question seems “nooby” but I need help making a cleaner/working sum calculator. I would greatly appreciate it if someone can take a look at this code and hopefully help me improve it. Thank you!

Final Edit:

Thank you all for the informative answers! I learned alot (for a “newbie” =]). I used Talon876’s answer for my calculator. Thanks again everyone!

Answer 1

If you want a single string to be printed on multiple lines, put a \n in the string.
For example,

print "This is on the first line\nThis is on the second line"

would output

This is on the first line
This is on the second line

It looks like you’re mixing a while loop with recursion (calling a method from within itself). I would suggest using a single while loop and an input variable to check for the breaking condition (the input is < 0)

It would look something like this:

sum = 0
number = float(input('Please enter in a positive number: '))
while number > 0:
    sum = sum + number
    number = float(input('If you are finished please enter a negative number.' + \ 'Otherwise, enter another positive number: ')) #fix this line using the information from the first part of the answer

This will loop until the user inputs a negative number, or 0. If you want to accept 0 as a positive number, change the while condition to number > -1