a) Write the code for the following function prototype // is_vowel(c) returns true if character c is a vowel and false otherwise. bool is_vowel(char cl; NOTE: The letters to be considered vowels in your program: 'a,, e', i', o,,"u'. Make sure that your function recognizes the uppercase vowel letters as well. b) Write the code for the following function prototype // count_vowels(s) returns the number of vowels in string s. int count_vowels(string s)