title: point to the last element in a Mat in opencv / c++
body: <p>How to point to the last element in a Mat in opencv?</p>
  
  <p>this is what I have done until now...seems incorrect :(</p>
  
  <pre><code>Mat Bdst;
  pToLastValue = Bdst.ptr&lt;float&gt;(0);  // pointer to row 0
  std::vector&lt; float &gt; vec(pToLastValue, pToLastValue+Bdst.cols); // construct a vector 
  float* pToLastValue = &amp;vec.back();
  </code></pre>
  
  <p>thanks in advance!</p>