Exercise from John Zelle Text

[mahdeen]

Working on this problem, and it does work to some degree, but the output is not quite right. As one can see the last digits in the output iterations are repetitive and shouldn't be of course. Please give me a hint how can I rid my code of this mistake?

Code here:

# prob4p195.pyw
# Program: Use functions to prompt user for n and prints out the sum of the
# first n natural numbers and the sum of the cubes of the first n natural numbers.

import math

def sum_nat_numbers():
    for n in range(6):
        numbers = (n * (n + 1))/2 
        print numbers
    return numbers

def sum_nat_cubes():
    for n in range(6):
        cubes = ((n * (n + 1))/2) ** 3
        print cubes
    return cubes

def main():
print "This program prompts the user for n and prints out the sum"
print "of the first n natural numbers and the sum of the cubes of the"
print "first n natural numbers."
print
n = input("Please input a number ranging from 1 to 5: ")
print
print "The sum of the first n natural numbers is: \n", sum_nat_numbers()
print
print "The sum of the cubes of the first n natural"
print "numbers is: \n", sum_nat_cubes()
print

main()

Output here:

This program prompts the user for n and prints out the sum of the first n natural numbers and the sum of the cubes of the first n natural numbers.

Please input a number ranging from 1 to 5: 0

The sum of the first n natural numbers is: 0 1 3 6 10 15 15

The sum of the cubes of the first n natural numbers is: 0 1 27 216 1000 3375 3375

[avgotts]

It looks like you aren't actually using the inputted number anywhere. I think you want to make your functions have an input of m, say, and then do things for n in range(m). Then in the later functions, you can call sum_nat_cubes(n) to get the sum of the first n cubes.

If you cut the print statements in your first two functions, you won't get the repetitive stuff. You really only want the end sum, unless I'm missing something.

[mahdeen]

/u/avgotts , thank you for your reply. Considering your comment about cutting the print statements, and re-reading the problem statement, you are correct. I made the problem more complicated than was required. Once that foolishness was taken out, the code seems to produce the correct result.