title: How do I get the dimensions (nestedness) of a nested vector (NOT the size)?
body: <p>Consider the following declarations:</p>
  
  <pre><code>vector&lt;vector&lt;int&gt; &gt; v2d;
  vector&lt;vector&lt;vector&lt;string&gt;&gt; &gt; v3d;
  </code></pre>
  
  <p>How can I find out the "dimensionality" of the vectors in subsequent code? For example, 2 for v2d and 3 for v3d?</p>