"""
Goal/purpose: This is a debugging exercise to be solved in class.  The program 
attempts to sum the numbers 0.1 through 0.9, in steps of 0.1 The correct answer 
is 4.5, but neither loop finds it.

(1) Why don't the loops terminate when we want them to?
(2) Replace the conditionals in the two while statements so the loops end right 
    after adding 0.9 into the sum. (There are lots of ways to do this.)
    
Consider using the debugger to run the script with a breakpoint set inside 
the second loop.

Author: George Gollin
File: unit03_in_class_warmup.py 
Date: June 8, 2017

Physics 298 owl, University of Illinois at Urbana-Champaign

"""

print("\nthe correct answer is 4.5")

# Define and initialize variables, then loop
sum = 0.0
term = 0.1
increment = 0.1
last_term = 0.9

# here's the loop
while term != last_term + increment:

    sum = sum + term
    term = term + increment
    
    if term > 100000:
        print("uh oh, first loop didn't terminate, so breaking now...")
        break
    
# End of loop. Print the results.
print("first loop result... sum is ", sum)

# try again. Initialize variables, then do the loop
sum = 0.0
term = 0.1

while term < last_term + increment:

    sum = sum + term
    term = term + increment     # set a breakpoint at this line
    
# End of loop. Print the results.
print("second loop result... ", sum)

# all finished.