title: Passing vectors by reference
body: <p>If I have a vector of objects in one class which I want to change in another, I would try and pass all the information by reference.</p>
  
  <p>What exactly do I need to pass by reference though? The vector? The objects? Both?</p>
  
  <p>Essentially what I'm asking is: What is the difference between these?</p>
  
  <pre><code>vector&amp;&lt;object&gt; blah; // A reference to a vector of objects?
  
  vector&lt;object&amp;&gt; blah; // A vector of references to objects?
  
  vector&amp;&lt;object&amp;&gt; blah; // A reference to a vector of references to objects???
  </code></pre>
  
  <p>I'm not actually sure how referencing of array like containers work. Are these legal?</p>