#include <string_view> // C++17
#include <vector>

auto split(std::string_view input, std::string_view separator = " ")
{
  std::vector<std::string_view> result;
  std::string_view::size_type position, start = 0;

  while (std::string_view::npos != (position = input.find(separator, start)))
  {
    result.push_back(input.substr(start, position-start));
    start = position + separator.size();
  }

  result.push_back(input.substr(start));
  return result;
}