What is the right approach when using STL container for median calculation?

Question

Let\'s say I need to retrieve the median from a sequence of 1000000 random numeric values.

If using anything but std::list, I have no (

Answer 1

Here's a more complete version of Mike Seymour's answer:

// Could use pass by copy to avoid changing vector
double median(std::vector &v)
{
  size_t n = v.size() / 2;
  std::nth_element(v.begin(), v.begin()+n, v.end());
  int vn = v[n];
  if(v.size()%2 == 1)
  {
    return vn;
  }else
  {
    std::nth_element(v.begin(), v.begin()+n-1, v.end());
    return 0.5*(vn+v[n-1]);
  }
}

It handles odd- or even-length input.