'''Some simple recursive functions.

Jeff Ondich, 12 Feb 2007

These functions illustrate some simple recursion.
'''

def iterativeFactorial(n):
    '''
    Returns the factorial of the integer n (or 1 if n is less than zero).
    '''
    print 'iterativeFactorial:', n
    product = 1
    for k in range(2, n + 1):
        product = product * k

    return product

def recursiveFactorial(n):
    '''
    Returns the factorial of the integer n.
    '''
    print 'recursiveFactorial:', n
    if n == 1:
        print 'recursiveFactorial ending:', n, 1
        return 1

    result = n * recursiveFactorial(n - 1)
    print 'recursiveFactorial ending:', n, result
    return result

def iterativeFibonacci(n):
    '''
    Returns the nth Fibonacci number.  Note that n should start counting at
    1, so 1 1 2 3 5 8 are the first through sixth Fibonacci numbers
    (not the zeroth through fifth).
    '''
    previous = 1
    current = 1
    for k in range(n-2):
        next = current + previous
        previous = current
        current = next

    return current

def recursiveFibonacci(n):
    '''
    Returns the nth Fibonacci number.  Note that n should start counting at
    1, so 1 1 2 3 5 8 are the first through sixth Fibonacci numbers
    (not the zeroth through fifth).
    '''
    if n <= 2:
        return 1

    return recursiveFibonacci(n - 1) + recursiveFibonacci(n - 2)

def printList(theList):
    '''
    Prints the given list, one item per line.
    '''
    if len(theList) > 0:
        print theList[0]
        printList(theList[1:])

def isPalindrome(s):
    '''
    Returns true if the string s is a palindrome
    '''
    pass


if __name__ == '__main__':
    n = input('Number, please: ')
    print 'n! =', iterativeFactorial(n), '(iterative)'
    print 'n! =', recursiveFactorial(n), '(recursive)'
    print

#    print 'The first', n, 'Fibonacci numbers (iterative)'
#    for k in range(n):
#        print iterativeFibonacci(k + 1),
#    print
#    print

#    print 'The first', n, 'Fibonacci numbers (recursive)'
#    for k in range(n):
#        print recursiveFibonacci(k + 1),
#    print
#    print
#
#    someList = ['cow', 'coatimundi', 'capybara', 'clam']
#    printList(someList)
#    print