4elist1204.cpp

《21天学通C＋＋》附盘的原代码。书上的每个例子在这里都有相应的C语言程序。

//Listing 12.4 Overloading constructors in derived classes

#include <iostream>
using namespace std;

enum BREED { GOLDEN, CAIRN, DANDIE, SHETLAND, DOBERMAN, LAB };

class Mammal
{
public:
	// constructors
	Mammal();
	Mammal(int age);
	~Mammal();

	//accessors
	int GetAge() const { return itsAge; }
	void SetAge(int age) { itsAge = age; }
	int GetWeight() const { return itsWeight; }
	void SetWeight(int weight) { itsWeight = weight; }

	//Other methods
	void Speak() const { cout << "Mammal sound!\n"; }
	void Sleep() const { cout << "shhh. I'm sleeping.\n"; }


protected:
	int itsAge;
	int itsWeight;
};

class Dog : public Mammal
{
public:

	// Constructors
	Dog();
	Dog(int age);
	Dog(int age, int weight);
	Dog(int age, BREED breed);
	Dog(int age, int weight, BREED breed);
	~Dog();

	// Accessors
	BREED GetBreed() const { return itsBreed; }
	void SetBreed(BREED breed) { itsBreed = breed; }

	// Other methods
	void WagTail() const { cout << "Tail wagging...\n"; }
	void BegForFood() const { cout << "Begging for food...\n"; }

private:
	BREED itsBreed;
};

Mammal::Mammal():
itsAge(1),
itsWeight(5)
{
	cout << "Mammal constructor...\n";
}

Mammal::Mammal(int age):
itsAge(age),
itsWeight(5)
{
	cout << "Mammal(int) constructor...\n";
}

Mammal::~Mammal()
{
	cout << "Mammal destructor...\n";
}

Dog::Dog():
Mammal(),
itsBreed(GOLDEN)
{
	cout << "Dog constructor...\n";
}

Dog::Dog(int age):
Mammal(age),
itsBreed(GOLDEN)
{
	cout << "Dog(int) constructor...\n";
}

Dog::Dog(int age, int weight):
Mammal(age),
itsBreed(GOLDEN)
{
	itsWeight = weight;
	cout << "Dog(int, int) constructor...\n";
}

Dog::Dog(int age, int weight, BREED breed):
Mammal(age),
itsBreed(breed)
{
	itsWeight = weight;
	cout << "Dog(int, int, BREED) constructor...\n";
}

Dog::Dog(int age, BREED breed):
Mammal(age),
itsBreed(breed)
{
	cout << "Dog(int, BREED) constructor...\n";
}

Dog::~Dog()
{
	cout << "Dog destructor...\n";
}
int main()
{
	Dog fido;
	Dog rover(5);
	Dog buster(6,8);
	Dog yorkie (3,GOLDEN);
	Dog dobbie (4,20,DOBERMAN);
	fido.Speak();
	rover.WagTail();
	cout << "Yorkie is " << yorkie.GetAge() << " years old\n";
	cout << "Dobbie weighs ";
	cout << dobbie.GetWeight() << " pounds\n";
	return 0;
}