"""This module contains code from
Think Python by Allen B. Downey
http://thinkpython.com

Copyright 2012 Allen B. Downey
License: GNU GPLv3 http://www.gnu.org/licenses/gpl.html

http://www.cartalk.com/content/seeing-double
"""

def is_triple_double(word):
    """Tests if a word contains three consecutive double letters."""
    i = 0
    count = 0
    while i < len(word)-1:
        if word[i] == word[i+1]:
            count = count + 1
            if count == 3:
                return True
            i = i + 2
        else:
            count = 0
            i = i + 1
    return False


def find_triple_double():
    """Reads a word list and prints words with triple double letters."""
    fin = open('words.txt')
    for line in fin:
        word = line.strip()
        if is_triple_double(word):
            print word


print 'Here are all the words in the list that have'
print 'three consecutive double letters.'
find_triple_double()
print ''