title: Grouping similar types of member variables together
body: <p>When writing a class do you group members variables of the same type together?  Is there any benefit to doing so?  For example:</p>
  
  <pre><code>class Foo
  {
  private:
      bool a_;
      bool b_;
      int c_;
      int d_;
      std::string e_;
      std::string f_;
      ...
  };
  </code></pre>
  
  <p>As opposed to:</p>
  
  <pre><code>class Bar
  {
  private:
      std::string e_;    
      bool a_;
      int d_;
      bool b_;
      std::string f_;
      int c_;    
      .
  </code></pre>
  
  <p>..
  };</p>
  
  <p>Or do you simply have them in the order they were added?</p>