63 lines
2.1 KiB
C++
63 lines
2.1 KiB
C++
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// fig10_47.cpp
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// Using virtual base classes.
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#include <iostream>
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// class Base definition
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class Base {
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public:
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virtual void print() const = 0; // pure virtual
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};
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// class DerivedOne definition
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class DerivedOne : virtual public Base {
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public:
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// override print function
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void print() const override {std::cout << "DerivedOne\n";}
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};
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// class DerivedTwo definition
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class DerivedTwo : virtual public Base {
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public:
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// override print function
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void print() const override {std::cout << "DerivedTwo\n";}
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};
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// class Multiple definition
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class Multiple : public DerivedOne, public DerivedTwo {
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public:
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// qualify which version of function print
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void print() const override {DerivedTwo::print();}
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};
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int main() {
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Multiple both; // instantiate Multiple object
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DerivedOne one; // instantiate DerivedOne object
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DerivedTwo two; // instantiate DerivedTwo object
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Base* array[3];
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array[0] = &both; // allowed now
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array[1] = &one;
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array[2] = &two;
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// polymorphically invoke function print
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for (int i = 0; i < 3; ++i) {
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array[i]->print();
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}
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}
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/**************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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