Defining Class BitVector - 4: Implementation Plan

class BitVector
{
  ...
private:
  // data
  uint8_t *  byteArray_;
  size_t     byteArraySize_;

  // methods
  size_t     ByteNumber (size_t indx) const;
  uint8_t    Mask       (size_t indx) const; // <-- make this static
};