''' Purpose: repeatedly prompt the user until they reply with a yes
        or no. The case of the letters do not matter.
'''

looking_for_a_yes_or_no = True
# have_found_a_yes_or_no = False
# while ( have_found_a_yes_or_no == False ): is also a totally valid while condition
# as long as the ENTIRE expression is True, the while loop continues to run
# as long as you keep track of what your condition is and how you change it,
    # you should be able to get the same output

while ( looking_for_a_yes_or_no == True ):
    print( "looking_for_a_yes_or_no is", looking_for_a_yes_or_no )
    reply = input( "Enter (yes / no): " )
    reply = reply.lower()

    # Several valid algorithms! And one not-so-valid algorithm.

    # if ( ( reply == 'yes' ) or ( reply == 'no' ) ):
    #     # THIS IS NOT AN IF LOOP; THIS IS AN IF STATEMENT IN A WHILE LOOP
    #     looking_for_a_yes_or_no = False

    # if ( reply == 'yes' ):
    #     looking_for_a_yes_or_no = False  # if this line isn't here, the while loop will go on forever
    #     # if you don't set the condition to be False at some point, the while loop will never end
    # elif ( reply == 'no' ):
    #     looking_for_a_yes_or_no = False

    # if ( reply == 'yes' ):
    #     looking_for_a_yes_or_no = False
    # if ( reply == 'no' ):
    #     looking_for_a_yes_or_no = False
    # Please don't do this.

    if ( reply in ['yes', 'no'] ):
        looking_for_a_yes_or_no = False  # this sets looking_for_a_yes_or_no equal to False so that the loop STOPS
    else:
        pass

print( "looking_for_a_yes_or_no is", looking_for_a_yes_or_no )

print( "Your reply of", reply, "is acceptable!" )



# while loop:
# like a for loop, a while loop helps us repeat an action
# we know how many times we need to iterate with a for loop (or we have an idea of it based on
    # user input), but the while loop just repeats based on a certain condition
# the while loop repeats when the boolean expression in parentheses is True and stops when it's False,
    # so make sure you are appropriately keeping track of the condition's boolean value
# anything you can do with a for loop, you can do with a while loop, and vice versa!
# if it helps, have an analogy!
# You've lost your shoe in your bedroom. You can tell yourself: "For every object in this room (the bed,
    # the bookshelf, the closet, etc.), I'll check for my shoe." That's like a for loop.
    # OR you can tell yourself: "While I haven't found my shoe, I will examine objects in my room."
    # (or "Until I've found my shoe, I will examine objects in my room.") That's like a while loop.