As you stated, each object as a vector. This does not conflict with the idea of having a vector of these objects:
Originally Posted by Veneficvs
friend std::istream& operator>>(std::istream& in, Box& box);
std::istream& operator>>(std::istream& in, Box& box)
// Read a line from in into a std::string.
// Initialise a std::stringstream with that std::string.
// Extract from the std::stringstream into box.numbers.