// P78.cpp class Object { }; class DB_Operation : public Object // must have a base class { }; template class DB_Set { static DB_Operation& get_cardinality_selection() { static DB_Operation x; return x; } public: static DB_Operation& _cardinality_selection; }; template DB_Operation& DB_Set::_cardinality_selection = DB_Set::get_cardinality_selection(); class PP_Container_Class_Property { }; class PP_Component { }; class PP_Class { public: DB_Set _employments; DB_Set _components; }; int main() { PP_Class u1; return &u1._employments._cardinality_selection == &u1._components._cardinality_selection; }