title: Removing duplicate characters from string using STL
body: <p>Is there a way to remove duplicate characters from a string like they can be removed from vectors as below </p>
  
  <pre><code>sort( vec.begin(), vec.end() );
  vec.erase( unique( vec.begin(), vec.end() ), vec.end() );
  </code></pre>
  
  <p>or do I just have to code up a basic solution for it?
  What I have thought:</p>
  
  <p>I could add all the characters into a set</p>