template<class charT, class traits, class Allocator>
  bool operator> (const basic_string<charT, traits, Allocator>& lhs,
                  const basic_string<charT, traits, Allocator>& rhs) noexcept;
Returns:
lhs.compare(rhs) > 0. template<class charT, class traits, class Allocator>
  bool operator> (const charT* lhs,
                  const basic_string<charT, traits, Allocator>& rhs);
Returns:
rhs.compare(lhs) < 0. template<class charT, class traits, class Allocator>
  bool operator> (const basic_string<charT, traits, Allocator>& lhs,
                  const charT* rhs);
Returns:
lhs.compare(rhs) > 0.