static size_t length(const T *seq)
Returns the number of elements in sequence seq1.
Note that seq1 may or may not end with a trailing '', it is completely user's responsibility for this decision, though seq[0], seq[1],... seq[length - 1] are all sequence seq's memory.
Following are char_traits funcitons, which make this class char_traits compatiable, so that it can be used in std::basic_string template, and be manipulated by the c++ stl algorithms.