title: C++, insert substring at specific place of a string
body: <p>I was trying to insert a substring into a string in C++ using</p>
  
  <pre><code>mystr = std::string("This is a '%s' string", "beautiful");
  </code></pre>
  
  <p>But it doesn't work... </p>
  
  <p>Do I really have to rely on the <code>stringstream</code> option if I am to use the syntax <code>%s</code>, or am I using the syntax incorrectly?</p>