Question 2 (15 points). Write a function that gets a string str, changes all lower case letters to * (asterisk), and all upper case letters to $ (dollar sign). All other characters remain unchanged. The function returns the total number of letters modified. int hide_letters (char* str); For example: - If str is "12 ab0", then the function changes it to "12**0", and returns 2. If stris "aBCDe*", then the function changes it to "*$$$**", and returns 5. If str is "0123&***", then the function keeps the string as is, and returns 0. An empty string is also a string