title: What is a permuted index?
body: <p>I am reading Accelerated C++. I don't understand Exercise 5-1:</p>
  
  <blockquote>
    <p>Design and implement a program to produce a permuted index from the following input. A permuted index is one in which each phrase is indexed by every word in the phrase.</p>
  </blockquote>
  
  <pre>
       The quick      brown fox 
  jumped over the     fence
  The quick brown     fox 
                      jumped over the fence
           jumped     over the fence
              The     quick brown fox 
      jumped over     the fence
                      The quick brown fox
  </pre>
  
  <p>That explanation isn't clear to me. What exactly is a permuted index?</p>