title: Initializing const c++ class without constructor
body: <p>I have a class which is used in a union, and therefore cannot have a (<em>non-trivial</em>) constructor.   I need to create a const instance of the class, can this be done?</p>
  
  <p>i.e.:</p>
  
  <pre><code> class Foo {
       // no constructors...
       private:
           int i;
   };
  
   union {
       Foo foo;
       Bar bar;
   } FooBar;
  
   const Foo defaultFoo = ???
  </code></pre>