You are given a string of any length. Return a new string consisting of the first and last characters concatenated together. You cannot use the at() member function or the subscript operator []. If the is less than length 2, return the original string. Complete the following file: main.cpp 1 2 3 4 5 #include using namespace std; /** Returns a string consisting of the first and last characters. @param s the string to processes @return the first and last characters concatenated together. */ string firstLast(const string& s) { // Write your function here 6 7 8 9 10 11 12 } Submit