title: Initialization Order of Class Data Members
body: <p>In the following code, when the ctor of <code>X</code> is called will the ctor of <code>A</code> or <code>B</code> be called first? Does the order in which they are placed in the body of the class control this? If somebody can provide a snippet of text from the C++ standard that talks about this issue, that would be perfect.</p>
  
  <pre><code>class A {};
  class B {};
  class X
  {
   A a;
   B b;
  };
  </code></pre>