Write a recursive method called isDupledrome that take a
String as an argument and that returns a boolean indicating whether
the word is a dupledrome.
Think about whether there are any helper methods like first,
last and middle that will make this program easier to
write. What are the preconditions for the helper methods?
2.
Test your method extensively to make sure it works
for all words, even weird ones like the empty string.
Using the Guardian Pattern, see if you can ``prove'' that
it is impossible for your method to cause an exception.
3.
Write an iterative version called isItDupledrome.
Be careful not to get the recursive and iterative versions
confused. They will look very different. I find it useful
to draw a picture of the string and the indices.
