title: Error Message: "no match for 'operator+='" after using "string* +="
body: <p>i have a problem with c++. I used a string pointer and wanted to add a other string dynamically. 
  But then i've got this errormessage:</p>
  
  <blockquote>
    <p>no match for 'operator+=' (operand types are 'std::__cxx11::string* {aka std::__cxx11::basic_string*}' and 'std::__cxx11::string {aka std::__cxx11::basic_string}')</p>
  </blockquote>
  
  <pre><code>void Stammbaum::printTree(Node* node, string* s){
      printLeftTree(node, s, 0);
  }
  
  void Stammbaum::printLeftTree(Node* node, string* s, int i){
      if(node == NULL)
          return;
  
      if(i != 0)
          printLeftTree(node-&gt;Mutter, s, 1);
  
      string temporaryString;
      temporaryString = "/-- " + node-&gt;vorname + " " + node-&gt;nachname + "\n";
      s += temporaryString;                     &lt;------------------------------Getting the error in this Line--
  
      printLeftTree(node-&gt;Vater, s, 1);
  }
  </code></pre>