63 lines
2.1 KiB
C++
63 lines
2.1 KiB
C++
// fig10_47.cpp
|
|
// Using virtual base classes.
|
|
#include <iostream>
|
|
|
|
// class Base definition
|
|
class Base {
|
|
public:
|
|
virtual void print() const = 0; // pure virtual
|
|
};
|
|
|
|
// class DerivedOne definition
|
|
class DerivedOne : virtual public Base {
|
|
public:
|
|
// override print function
|
|
void print() const override {std::cout << "DerivedOne\n";}
|
|
};
|
|
|
|
// class DerivedTwo definition
|
|
class DerivedTwo : virtual public Base {
|
|
public:
|
|
// override print function
|
|
void print() const override {std::cout << "DerivedTwo\n";}
|
|
};
|
|
|
|
// class Multiple definition
|
|
class Multiple : public DerivedOne, public DerivedTwo {
|
|
public:
|
|
// qualify which version of function print
|
|
void print() const override {DerivedTwo::print();}
|
|
};
|
|
|
|
int main() {
|
|
Multiple both; // instantiate Multiple object
|
|
DerivedOne one; // instantiate DerivedOne object
|
|
DerivedTwo two; // instantiate DerivedTwo object
|
|
Base* array[3];
|
|
|
|
array[0] = &both; // allowed now
|
|
array[1] = &one;
|
|
array[2] = &two;
|
|
|
|
// polymorphically invoke function print
|
|
for (int i = 0; i < 3; ++i) {
|
|
array[i]->print();
|
|
}
|
|
}
|
|
|
|
/**************************************************************************
|
|
* (C) Copyright 1992-2022 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. *
|
|
**************************************************************************/
|
|
|