error c2036 : unknown size if structure
<p>I have 2 class(A &amp; C) defined in a file <code>allocate.h</code> and class B defined in <code>work.h</code>.<br>
I included allocate.h inside work.h file<br>
My code looks like :  </p>

<pre><code>Class A{  
}  

Class C
{  
public:  
    struct xyz{  
        A ob;  
    };  
}  

include"allocate.h"   
Class C;   
Class B{  
  void test(){  
      xyz obj; // `Error : error c2036 : xyz unknown size`  
  }  
}  
</code></pre>

<p>Can someone tell me how can i communicate the size of xyz structure in function test?</p>
