Remove a useless class variable for ranges.

    starts.push_back(0);

    ends.push_back(-1);

    strand = 1;

    range_num = 1;

    default_range = true;

  }

    std::sort(starts.begin(), starts.end());

    std::sort(ends.begin(), ends.end());

    range_num = starts.size();

    const int num_ranges = starts.size();

    if (ends[0] == -1) {

      for (i = 0; i < range_num - 1; ++i) {

      for (i = 0; i < num_ranges - 1; ++i) {

        ends[i] = ends[i + 1];

      }

      ends[i] = -1;

    int i, j, k;

    i = 0;

    for (k = 0; k < range_num; ++k) {

    const int num_ranges = starts.size();

    for (k = 0; k < num_ranges; ++k) {

      int start = starts[k];

      int end = ends[k];

 private:

  std::vector<int> starts;

  std::vector<int> ends;

  int range_num;

  int strand;

  // Whether the range has been modified by new input.

  bool default_range;