title: Parameters in meanStdDev function
body: <p>I have the following code:</p>
  
  <pre><code>Scalar m;   //Scalar is a class for a 4 variable vector. m is its instance.        
  Scalar std;
  meanStdDev(hist, m, std);
  </code></pre>
  
  <p>It works well but it doesn't work for the following.</p>
  
  <pre><code>vector &lt; float &gt; m;
  vector &lt; float &gt; std;
  meanStdDev(hist, m, std);
  </code></pre>
  
  <p>I am not able to understand the problem as here also I am creating a vector just like in the case of Scalar. Please explain.</p>