title: Vector of vectors (char): core dumped
body: <p>This may be a stupid question, but I simply can't work out why this throws a segmentation fault(core dumped):</p>
  
  <pre><code>#include &lt;vector&gt;
  using namespace std;
  vector&lt; vector&lt;char&gt; &gt; samplevct;
  int main(void)
  {
      samplevct[0].push_back('a');
      return 0;
  }
  </code></pre>
  
  <p>Might someone explain why this doesn't work?</p>
  
  <p>I use g++, Fedora 20, if this is an information of importance.
  Thanks in advance</p>