title: Confusing C++ code involving *this?
body: <p>Could someone explain this code?  I don't understand line 3:</p>
  
  <pre><code>MyString MyString::operator+(const MyString &amp;str)
  {
      MyString ss(*this); //----&gt; explain this part
      ss += str;
      return ss;
  }
  </code></pre>
  
  <p>Thanks!</p>