Fix Factorial errors

[Srishanth905]

corrected the errors in the factorial code and updated the implementation.
Changes made :

• Corrected syntax and logical errors in the factorial code.
• Ensured the factorial calculation works correctly for the given input.
• Improved the structure and readability of the code .
• Tested the program to confirm the correct output.

These changes make the factorial program more reliable and easier to understand.