title: Convert valarray to basic array
body: <p>We can initialize a <code>valarray</code> from a basic user defined array as following:</p>
  
  <pre><code>int arr[3]={0};
  valarray&lt;int&gt; test(arr, sizeof(arr)/sizeof(int));
  </code></pre>
  
  <p>How can we move the other way around? Suppose we have a <code>valarray&lt;int&gt;</code> and we need to convert back to a basic user defined array? I didn't find anything in the documentation.</p>