How would you reverse a string without using libraries, and also change the first letter to uppercase and the last letter to lowercase?
Implement reverse_and_change_case(s) without using string slicing, reversed(), .upper(), or .lower(). Return the transformed string. Inputs contain ASCII letters only. For an empty string, return an empty string. For a one-character string, uppercase that character.
s is a string, and the function returns a string.
def reverse_and_change_case(s):