'''
   recursivefunctions.py
   
   Jeff Ondich, 11/1/09
   
   Some simple recursive functions.

   -- In each function, what is (are) the base case(s)?

   -- What happens if you call factorial(100)?  How about fibonacci(100)?
      Why is fibonacci(100) problematic?
'''

import sys

def factorial(n):
    if n <= 1:
        return 1
    else:
        return n * factorial(n - 1)

def fibonacci(n):
    if n <= 1:
        return 1
    else:
        return fibonacci(n - 2) + fibonacci(n - 1)

def isPalindrome(s):
    if len(s) <= 1:
        return True
    if s[0] != s[-1]:
        return False
    else:
        return isPalindrome(s[1:-1])

def printBackwards(s):
    if len(s) == 0:
        pass
    else:
        printBackwards(s[1:])
        sys.stdout.write(s[0])

def getReversedString(s):
    if len(s) == 0:
        return ''
    else:
        return getReversedString(s[1:]) + s[0]