72. Implement Custom strcmp function

You are given two null-terminated strings.

Your task is to:

• Compare them character by character using ASCII values
• Return:
  
  • 0 if all characters are the same and both strings end at the same time
  • If mismatched: ASCII difference of the first mismatched characters. I.e. positive value if the first non-matching character in string a is greater than that in string b or negative value (vice-versa)

Do not use built-in functions like strcmp().

Example-1

Input: "apple" and "apple"
Output: 0

Example-2

Input: "cat" and "bat"
Output: 1 
(because 'c' - 'b' = 1)

Example-3

Input: "abc" and "abcd"
Output: -100 
(because 'a'-'a'=0, 'b'-'b'=0, 'c'-'c'=0, then '\0' - 'd' = -100)