title: Stream format flags for fixed width IO-Manipulator
body: <p>I'm using this code to convert an integer to string with fixed width:</p>
  <pre><code>uint32_t number = 2; // 0-99
  
  std::ostringstream ss;
  ss &lt;&lt; std::setw(2) &lt;&lt; std::setfill('0') &lt;&lt; number;
  
  return ss.str();
  </code></pre>
  <p>However, recently I came across another version, where the format flags are specified (I put it to an extra line for visibility):</p>
  <pre><code>uint32_t number = 2; // 0-99
  
  std::ostringstream ss;
  ss.setf(std::ios_base::internal, std::ios_base::adjustfield);
  ss &lt;&lt; std::setw(2) &lt;&lt; std::setfill('0') &lt;&lt; number;
  
  return ss.str();
  </code></pre>
  <p>What is the purpose of setting the output flags like this? The output is of course the same, like I would expect with <code>adjustfield</code>. Any reasons for using the second version?</p>