''' Purpose: play guess a number
'''

# specify max number
n = 100000

# start the game
print( 'Think of a number from 0 to', n )

lowest_possibility = 0
greatest_possibility = n

still_guessing = True # Boolean for our while loop ( while loop will run while
# this variable is True!

while( still_guessing == True ): # This loop will keep guessing
                            # until the Boolean is set to False!
                            # stil_guessing == True is the logical expression
                            # we're testing in the while loop!
                            # If it is, we keep running the loop.
                            # If it's not, we exit the loop.
    middle = ( lowest_possibility + greatest_possibility ) // 2

    prompt = "Is your number equal to " + str( middle ) + "? "

    reply = input( prompt )

    if ( reply == "yes" ):
        print( "Found it!" )
        still_guessing = False # Change boolean so that we stop guessing
                                # (so that while loop stops)

        # IMPORTANT: Update the Boolean (set it to false) when you
        # want to be done with the while loop!
        # In the guessing game, we want to assign still_guessing to False
        # when we find the number because then we're done and we don't want
        # the loop to run again!

    else:    # The Boolean is still true so keep running the while loop!
        prompt = "Is your number greater than " + str( middle ) + "? "
        reply = input( prompt )
        if ( reply == "yes" ):  # If it's greater than the middle
            lowest_possibility = middle + 1     # Update the range
        else:                   # If it's less than the middle

            greatest_possibility = middle - 1   # Update the range

        print( lowest_possibility, "...", greatest_possibility )
        # Show us our new range and keep running the loop (go back to
        # start of while loop until we find it)
        # We run the loop again with the new updated range (lowest_possibility
        # and greatest_possibility and middle are updated now)