title: Concatenating strings doesn't work as expected
body: <p>I know it is a common issue, but looking for references and other material I don't find a clear answer to this question.</p>
  
  <p>Consider the following code:</p>
  
  <pre><code>#include &lt;string&gt;
  
  // ...
  // in a method
  std::string a = "Hello ";
  std::string b = "World";
  std::string c = a + b;
  </code></pre>
  
  <p>The compiler tells me it cannot find an overloaded operator for <code>char[dim]</code>.</p>
  
  <p>Does it mean that in the string there is not a + operator?</p>
  
  <p>But in several examples there is a situation like this one. If this is not the correct way to concat more strings, what is the best way?</p>