title: Adding to middle of std::vector
body: <p>Is there a way to add values to the middle of a <code>vector</code> in C++?  Say I have:</p>
  
  <pre><code>vector &lt;string&gt; a;
  // a gets filled up with "abcd", "wertyu", "dvcea", "eafdefef", "aeefr", etc
  </code></pre>
  
  <p>and I want to break up one of the strings and put all of the pieces back into the <code>vector</code>.  How would I do that? the strings I break can be anywhere, index = 0, somewhere in the middle, or index = <code>a.size() - 1</code>.</p>