Programming Challenge: Palindrome Checker (Jan 1, 2025)

Challenge:

Write a program that checks if a given string is a palindrome. A palindrome is a word, phrase, number, or sequence of characters that reads the same backward as forward, ignoring spaces, punctuation, and capitalization.

Requirements:

1. Accept user input for the string.
2. Normalize the string by removing non-alphanumeric characters and converting it to lowercase.
3. Check if the normalized string is a palindrome.
4. Print True or False based on the result.

Bonus:

• Extend the program to handle numeric palindromes (e.g., 12321).
• Allow the user to check multiple strings in one run.

Example Output:

1. Input: "A man, a plan, a canal, Panama!"
   Output: True
2. Input: "Hello, World!"
   Output: False