title: std::stringstream vs std::string for concatenating many strings
body: <p>I know one of the advantages of <code>std::stringstream</code> is that it is a <code>std::istream</code> so it may accept input from any type that defines <code>operator&lt;&lt;</code> to <code>std::istream</code>, and also from primitives types.</p>
  
  <p>I am not going to use <code>operator&lt;&lt;</code>; instead I am just going to concatenate many strings. Does the implementation of <code>std::stringstream</code> make it faster than <code>std::string</code> for concatenating many strings?</p>