palindrome is a string that reads the same forward as well as backward. For example, "otto" and "never odd or even" are palindromes. When determining if a string is a palindrome, we ignore characters that are not letters. 1. Give a recursive definition of a palindrome. (Hint: Consider what you get if you remove the first and last letters of a palindrome.) 2. What is the base case of your definition? 3. Write a recursive program based on your definition that repeatedly prompts the user for a string and then reports whether the string is a palindrome. 4. Write an iterative program that does the same thing. 5. Compare your two programs in terms of time and space efficiency.