title: understanding container template parameter of `std::stack`
body: <p>What exactly does the second template parameter of <code>std::stack</code> represent? For example, in the following code, what does <code>std::vector&lt;int&gt;</code> imply?</p>
  
  <pre><code>std::stack&lt;int, std::vector&lt;int&gt;&gt; fourth(myvector);
  </code></pre>