How do I code (syntax) definitions of nested class?

See more:

C++

Can somebody write for me , as an example, definitions for the following declaration of nested class PLAIN_TEST_CLASS.
I just need a syntax sample.

This is just a test class and I need to keep declaration and definition separate.

#include "CAT_btscanner_global.h"
#include "common_header.h"


// declarations
class CAT_BTSCANNER_EXPORT CAT_btscanner
{
public:
    CAT_btscanner();            //TOK constructor
    void TestFunction (void);   // TOK 
    // nested class
    class PLAIN_TEST_CLASS
    {
        PLAIN_TEST_CLASS();
        void PLAIN_TestFunction (void );
    };
};

What I have tried:

Asked Mrs Google to give an example of nested classes with definitions. No luck.