Step-By-Step Collatz Sequence #2843

[BhavanKumarGM]

🔹 Collatz Sequence Problem

The Collatz sequence (also called the 3n + 1 problem) is a simple mathematical process:
1. Start with any positive integer n.
2. If n is even, divide it by 2 → n = n / 2.
3. If n is odd, multiply it by 3 and add 1 → n = 3n + 1.
4. Repeat this process with the new value of n.
5. Eventually (for all tested numbers), the sequence will reach 1.

Explaining the code part:
Description
When the user enters a non-integer (like "abc"), the program raises a ValueError and exits immediately. It would be better if the program handled this by showing an error message and requesting valid input again.

**Steps to reproduce**  
          1. Run the program (e.g., in Python).  
          2. Input “abc” instead of a number.

 **Expected behavior**  
          Program prints something like “Please enter a valid positive integer.” and then prompts again.

 **Actual behavior**  
          Program crashes with a traceback, e.g., `ValueError: invalid literal for int() with base 10: 'abc'`.

 **Suggested fix**  
          Wrap the input logic in a loop with `try/except`, and use `continue` in the except block to reprompt.

 **The Main Function**
             while True:
                       try:
                            num = int(input("Enter a positive integer: "))
                             if num > 0:
                                   break
                             else:
                                  print("Please enter a positive integer.")
                       except ValueError:
                                 print("Invalid input! Please enter a number.")
                                 continue
 **Conclusion** 
             This approach ensures the program doesn't crash on bad input and prompts the user again in a friendly way.

[BhavanKumarGM]

Kindly review this and let me know if any modifications are required.