# Palindrome.py 
#
# Description: Calls the Palindrome function (from Practice Exam #4 Q.9)
#              and prints 
#                 That’s a palindrome!
#              when the function returns True and
#                 That’s no palindrome!  
#              when then function returns False.
#
#              The program terminates when the user enters an empty string.
#
# Author: Anne Lavergne
# Date: Feb. 28 2024


def palindrome(aWord):
    """Returns True if 'aWord' is a palindrome and False it is not."""
 
    # The idea of this algorihtm is:
    # Imagine we are folding aWord in half and checking
    # whether each pair of matching letters are identical
    # If so, we have a palindrome
    
    # Get the positive index of the last (rightmost) letter of aWord
    reverseIndex = len(aWord)-1
    
    # Let's compare each letter of the leftmost half of aWord with
    # its matching counterpart letter in the rightmost half of aWord
    for anIndex in range(0,len(aWord)//2):

        # If the letters in the current pair are not identical
        # then aWord is not a palindrome        
        if aWord[anIndex] != aWord[reverseIndex]:
            return False

        # Go to the next pair of letters
        reverseIndex -= 1

    # If we reach this point, aWord is a palindrome 
    return True


# ***Main part of my program

theWord = input("Enter a word to check: ")
while theWord:
    if palindrome(theWord):
        print("That's a palindrome!")
    else:
        print("That's no palindrome!")
    theWord = input("Enter a word to check: ")