title: 3D vector constructor C++
body: <p>For a 2d vector, I know I can go:</p>
  
  <pre><code>vector&lt;vector&lt;T&gt;&gt; vec;
  vec = vector&lt;vector&lt;T&gt;&gt; (boardSize, vector&lt;T&gt;(boardSize));
  </code></pre>
  
  <p>But how do I do it for a 3d vector?</p>
  
  <p>I tried </p>
  
  <pre><code>vector&lt;vector&lt;vector&lt;T&gt;&gt;&gt; vec;
  vec = vector&lt;vector&lt;vector&lt;T&gt;&gt;&gt; (boardSize, boardSize, vector&lt;T&gt;(boardSize));
  </code></pre>
  
  <p>But it wouldn't compile. Any ideas?</p>