// Fig. 24.20: Fig24_20.cpp // Attempting to polymorphically call a function that is // multiply inherited from two base classes. #include using std::cout; using std::endl; // class Base definition class Base { public: virtual void print() const = 0; // pure virtual }; // end class Base // class DerivedOne definition class DerivedOne : public Base { public: // override print function void print() const { cout << "DerivedOne\n"; } // end function print }; // end class DerivedOne // class DerivedTwo definition class DerivedTwo : public Base { public: // override print function void print() const { cout << "DerivedTwo\n"; } // end function print }; // end class DerivedTwo // class Multiple definition class Multiple : public DerivedOne, public DerivedTwo { public: // qualify which version of function print void print() const { DerivedTwo::print(); } // end function print }; // end class Multiple int main() { Multiple both; // instantiate Multiple object DerivedOne one; // instantiate DerivedOne object DerivedTwo two; // instantiate DerivedTwo object Base *array[ 3 ]; // create array of base-class pointers array[ 0 ] = &both; // ERROR--ambiguous array[ 1 ] = &one; array[ 2 ] = &two; // polymorphically invoke print for ( int i = 0; i < 3; i++ ) array[ i ] -> print(); return 0; } // end main /************************************************************************** * (C) Copyright 1992-2005 by Deitel & Associates, Inc. and * * Pearson Education, Inc. All Rights Reserved. * * * * DISCLAIMER: The authors and publisher of this book have used their * * best efforts in preparing the book. These efforts include the * * development, research, and testing of the theories and programs * * to determine their effectiveness. The authors and publisher make * * no warranty of any kind, expressed or implied, with regard to these * * programs or to the documentation contained in these books. The authors * * and publisher shall not be liable in any event for incidental or * * consequential damages in connection with, or arising out of, the * * furnishing, performance, or use of these programs. * **************************************************************************/