title: Convert chrono::duration to string or C string
body: <p>I'm trying to make a table (a 9 by 11 array) that stores the amount of time taken by a function by several sorting functions.</p>
  
  <p>I think I want the table to be a string.  I currently cannot solve how to convert <code>chrono</code> to <code>string</code> and haven't been able to find any resources online.</p>
  
  <p>Do I need to abandon the string typing for the table, or is there a way to store these time differences in a string?</p>
  
  <pre><code>for (int i = 0; i&lt;8;i++) // sort 8 different arrays
  { 
      start = chrono::system_clock::now(); 
      //Sort Array Here
      end = chrono::system_clock::now();
      chrono::duration&lt;double&gt; elapsed_seconds = end-start;
      table[1][i] = string(elapsed_seconds)   // error: no matching conversion for functional style cast
  }
  </code></pre>