6.16-虚继承.cpp

Visual C++的课件

// Listing 13.6
// Virtual inheritance
#include <iostream.h>

typedef int HANDS;
enum COLOR { Red, Green, Blue, Yellow, White, Black, Brown } ;

class Animal        // common base to both horse and bird
{
public:
	Animal(int);
	virtual ~Animal() { cout << "Animal destructor...\n"; }
	virtual int GetAge() const { return itsAge; }
	virtual void SetAge(int age) { itsAge = age; }
private:
	int itsAge;
};

Animal::Animal(int age):
itsAge(age)
{
	cout << "Animal constructor...\n";
}

class Horse : virtual public Animal
{
public:
	Horse(COLOR color, HANDS height, int age);
	virtual ~Horse() { cout << "Horse destructor...\n"; }
	virtual void Whinny()const { cout << "Whinny!... "; }
	virtual HANDS GetHeight() const { return itsHeight; }
	virtual COLOR GetColor() const { return itsColor; }
protected:
	HANDS itsHeight;
	COLOR itsColor;
};

Horse::Horse(COLOR color, HANDS height, int age):
Animal(age),
itsColor(color),itsHeight(height)
{
	cout << "Horse constructor...\n";
}

class Bird : virtual public Animal
{
public:
	Bird(COLOR color, bool migrates, int age);
	virtual ~Bird() {cout << "Bird destructor...\n";  }
	virtual void Chirp()const { cout << "Chirp... ";  }
	virtual void Fly()const
				{ cout << "I can fly! I can fly! I can fly! "; }
	virtual COLOR GetColor()const { return itsColor; }
	virtual bool GetMigration() const { return itsMigration; }
protected:
	COLOR itsColor;
	bool itsMigration;
};

Bird::Bird(COLOR color, bool migrates, int age):
Animal(age),
itsColor(color), itsMigration(migrates)
{
	cout << "Bird constructor...\n";
}

class Pegasus : public Horse, public Bird
{
public:
	void Chirp()const { Whinny(); }
	Pegasus(COLOR, HANDS, bool, long, int);
	virtual ~Pegasus() {cout << "Pegasus destructor...\n";}
	virtual long GetNumberBelievers() const
			{ return  itsNumberBelievers; }
	virtual COLOR GetColor()const { return Horse::itsColor; }
private:
	long itsNumberBelievers;
};

Pegasus::Pegasus(
	COLOR aColor,
	HANDS height,
	bool migrates,
	long NumBelieve,
	int age):
	Horse(aColor, height,age),
	Bird(aColor, migrates,age),
	Animal(age*2),
	itsNumberBelievers(NumBelieve)
{
	cout << "Pegasus constructor...\n";
}

int main()
{
	Pegasus *pPeg = new Pegasus(Red, 5, true, 10, 2);
	int age = pPeg->GetAge();
	cout << "This pegasus is " << age << " years old.\n";
	delete pPeg;
	return 0;
}