title: String::push_back() does not push back
body: <p>I am currently writing a infix to postfix converter. It works pretty well except I have problems adding the rest of the Stack to the postfix. The stack is a</p>
  
  <pre><code>vector&lt;char&gt;
  </code></pre>
  
  <p>and the postfix is a String. After I'm done reading everything I try the following:</p>
  
  <pre><code>while (!stack.empty()) {
      postfix.push_back(stack.back());
      stack.pop_back();
  }
  </code></pre>
  
  <p>But there is nothing appended. I even tried it with Debug-mode and it seems fine, but nothing gets appended.</p>
  
  <pre><code>std::cout &lt;&lt; postfix.c_str();
  </code></pre>
  
  <p>Leaves out the last operator from the stack. I even tried to save it temporary, but it does not get pushed.</p>
  
  <p>I can not post all four files in pastebin because of the limit. I use Visual Studio 2010 Ultimate and there are no errors, just no character appended.</p>