# file: InClassAssignment3.py
# Here are the definitions for the following two functions presented:
# sumN(n) returns the sum of the first n natural numbers if n is a positive integer,
#         and -1 otherwise
# sumNSquares(n) returns the sum of squares of the first n natural numbers if n is a positive integer,
#         and -1 otherwise
#
# Program that has main function, in which it prompts a user for a positive integer,
# and produces sum of the first n integers and the sum of squares of the first n integers,
# using functions sumN and sumNSquares, correspondingly
#
# It also produces results into a file result.txt in the following format:
# The sum of the first <n> integers is: <result here>
# The sum of the squares of the first <n> integers is: <result here>


def sumN(n):
    # put the code here

def sumNSquares(n):
    # put the code here

def main():
    print("Hello. This program finds:\n\
1. The sum of the first n natural numbers, and\n\
2. The sum of the squares of the first n natural numbers.\n")

    try:

        n = int(input("Please, enter a natural number:"))

        s = sumN(n)

        sq = sumNSquares(n)

        answer1 = "The sum of first {0} natural numbers is {1},".format(n,s)
        answer2 = "The sum of the squares of the first {0} natural numbers is {1}.".format(n,sq)

        print(answer1)
        print(answer2)

        outSource = open("result.txt","w")
        print(answer1,file = outSource)
        print(answer2,file = outSource)
        outSource.close()
        
    except:
       print("incorrect input or something is wrong with the output source")
            

main()