You've written isVowel using Boolean evaluation. Now let's write vowelclass using the switch statement. The function returns O if the argument is not a vowel, if it is an uppercase vowel, and 2 if it is a lowercase vowel. Complete the following file: vowel.cpp 1 #include "vowel.h" 2 using namespace std; NM 4 5 6 Submit Use the following files: Tester.cpp #include #include using namespace std; #include "vowel.h" int main() { cout vowel.h @file vowel.h @author Stephen Gilbert @version cs 150 Spring 2021 #ifndef VOWEL_H #define VOWEL_H #include Classifies characters as upper-vowel, lower-vowel, not-vowel. @param c the character to process @return "upper" if uppercase, "lower" if lowercase, "none" if not a vowel. std::string vowelClass(char c); #endif