linear interpolation array c++

std::vector<double> ClassName::linspace(double a, double b, size_t N) {
  double h = (b - a) / static_cast<double>(N-1);
  vector<double> xs(N);
    vector<double>::iterator x;
  double val;
  for (x = xs.begin(), val = a; x != xs.end(); ++x, val += h)
    *x = val;
  return xs;
}