i have a vector of strings, split it in two

#include <vector>
#include <string>

std::vector<std::string> split(std::string my_string) {
  std::vector<std::string> vec;
  vec.push_back(my_string.substr(0, my_string.size()/2));
  vec.push_back(my_string.substr(my_string.size()/2, my_string.size()));
  return vec;
}