STL & Generic Programming: STL Function Objects and Their Adaptors

Listing 1: Querying a vector of vectors for the maximal size

max_size<std::vector<Something> > the_max =
std::for_each(
  vect_of_vects.begin(),
  vect_of_vects.end(),
  max_size<std::vector<Something> >()
  );
size_t m = the_max.get_max();

template<typename T>
class max_size
{
public:
  max_size() : m_max_size(0) {}
  
  size_t get_max() const
  { return m_max_size; }
  
  void operator()(const T& cont)
  { m_max_size = std::_cpp_max(cont.size(), m_max_size); }

private:
  size_t m_max_size;
};
— End of Listing —