"""
Goal/purpose: This is a debugging exercise to be solved in class. 

This program attempts to calculate e using its infinite series
e = sum(1/k!) for k from 0 to infinity. (Recall 0! = 1 by definition)

The correct answer is 2.7182818284590451, but the program (as written) doesn't
find it. Please fix the problem.

Author: George Gollin

File: unit04_in_class_warmup_solution.py 

Date: January 26, 2017

Physics 298 owl, University of Illinois at Urbana-Champaign

"""

print("\nthe correct answer is 2.7182818284590451...")

# Define and initialize variables, then loop
sum = 1.0
k = 0
kfactorial = 1
number_of_terms = 10

# here's the loop
while k < number_of_terms:

    k = k + 1
    kfactorial = kfactorial * k
    sum = 1 / kfactorial 
    
print("e = ", sum)

# all finished.