title: Sorting an array in reverse order
body: <p>I'm going over the logic behind the combined comparison operator and it's ability to reverse the sort order of an array. For example, I could reverse the order of the following array:</p>
  
  <pre><code>books = ["Charlie and the Chocolate Factory", "War and Peace", "Utopia", 
  "A Brief History of Time", "A Wrinkle in Time"]
  </code></pre>
  
  <p>by adding this line of code:</p>
  
  <pre><code>books.sort! { |firstBook, secondBook| secondBook &lt;=&gt; firstBook }
  </code></pre>
  
  <p>My question is, why would I not be able to just call:</p>
  
  <pre><code>books.reverse!
  </code></pre>
  
  <p>on this array to get the reverse order?</p>