title: Retrieve value from std::vector<cv::Point>::const_iterator
body: <p>I found a contour from an image. I want to find the min point and min point from the contours. </p>
  
  <pre><code>vector&lt;Point&gt; test = contours[0];
  auto mmx = std::minmax_element(test.begin(), test.end(), less_by_y);
  
  bool less_by_y(const cv::Point&amp; lhs, const cv::Point&amp; rhs)
  {
      return lhs.y &lt; rhs.y;
  }
  </code></pre>
  
  <p>I have tried this coding and it run successfully. But due to my stupidness, i do not know how to retrieve data from mmx. Anyone please help me?</p>
  
  <p>If i want to access the value of point y from contours, how to do it? I really confused with those data types.</p>