Write a method that takes in a string, splits it in half, and returns a new string with the first character of the first half, followed by the first character of the second half. For example, 'ABCDEFabcdef' becomes 'AaBbCcDdEeFf'. If the string has an odd number of characters, the middle character becomes the last character of the result.

Complete the following file:

prog.cpp

#include <iostream> #include <string> using namespace std; string merge_halves(string s) {
}