cc32b_demo-32dk2j_cpp_纯虚函数与抽象类2-txwtech

//纯虚函数是用来继承用的
//纯虚函数
//抽象类-抽象数据类型
//*任何包含一个或者多个纯虚函数的类都是抽象类
//*不要/不能创建这个类的对象，应该/只能继承它
//*务必覆盖从这个类继承的纯虚函数
//实现纯虚函数-----------可写可以不写
//C++接口
//就是只包含纯虚函数的抽象基类

//一个指向基类的指针可以指向它的派生类，指向它的子子孙孙
//通常在编程语句中用 abstract 修饰的类是抽象类。在C++中，含有纯虚拟函数的类称为抽象类，它不能生成对象；在java中，含有抽象方法的类称为抽象类，同样不能生成对象。

//抽象类是不完整的，它只能用作基类。在面向对象方法中，抽象类主要用来进行类型隐藏和充当全局变量的角色。

#include <iostream>//txwtech,cc32b_demo-纯虚函数与抽象类demo2
using namespace std;
//一个指向基类的指针可以指向它的派生类，指向它的子子孙孙
//通常在编程语句中用 abstract 修饰的类是抽象类。在C++中，含有纯虚拟函数的类称为抽象类，它不能生成对象；在java中，含有抽象方法的类称为抽象类，同样不能生成对象。//抽象类是不完整的，它只能用作基类。在面向对象方法中，抽象类主要用来进行类型隐藏和充当全局变量的角色。enum COLOR {Red,Green,Blue,Yellow,White,Black,Brown};class Animal
{
public:Animal(int);virtual ~Animal() { cout << "Animal析构函数被调用...\n"; }virtual int GetAge() const { return itsAge; }virtual void SetAge(int age) { itsAge = age; }virtual void Sleep() const = 0;//纯虚函数virtual void Eat() const = 0;virtual void Reproduce() const = 0;virtual void Move() const = 0;virtual void Speak() const = 0;private:int itsAge;
};
Animal::Animal(int age) :itsAge(age)
{cout << "Animal构造函数被调用。。。、\n";
}
class Mammal :public Animal
{
public:Mammal(int age) :Animal(age){cout << "Mammal构造函数被调用。。。\n";}virtual ~Mammal() { cout << "Mammal析构函数被调用..."; }virtual void Reproduce() const{cout << "Mammal Reproduction depiacted...\n";}
};
class Fish :public Animal
{
public:Fish(int age) :Animal(age){cout << "fish的构造函数被调用。。。\n";}virtual ~Fish(){cout << "fish的析构函数被调用。。。\n";}virtual void Sleep() const { cout << "fish snoring...\n"; }virtual void Eat() const { cout << "fish feeding...\n"; }virtual void Reproduce() const { cout << "fish laying eggs...\n"; }virtual void Move() const { cout << "fish swimming...\n"; }virtual void Speak() const {}};
class Horse :public Mammal
{
public:Horse(int age, COLOR color) :Mammal(age), itsColor(color){cout << "horse构造函数被调用。。。\n";}virtual ~Horse(){cout << "horse析构函数被调用。。。\n";}virtual void Speak() const {cout<<"Whinny!...\n";}virtual void Sleep() const {cout<<"Horse snoring ...\n";}virtual COLOR GetItsColor() const { return itsColor; }virtual void Eat() const { cout << "Horse feeding...\n"; }virtual void Move() const { cout << "horse running...\n"; }
protected: //虽然是私有，但可以被继承COLOR itsColor;};
class Dog :public Mammal
{
public:Dog(int age, COLOR color) :Mammal(age), itsColor(color){cout << "dog构造函数被调用\n";}virtual ~Dog(){cout << "dog析构函数被调用\n";}virtual void Speak() const { cout << "dog Whoof...\n"; }virtual void Sleep() const { cout << "dog Snoring...\n"; }virtual void Eat() const { cout << "dog Eatting...\n"; }virtual void Move() const { cout << "dog running...\n"; }virtual void Reproduce() const{cout << "Dogs reproducing...\n";}
protected:COLOR itsColor;};int main()
{Animal *pAnimal = 0;int choice;bool fQuit = false;while (fQuit == false){cout << "1.Dog 2.Horse 3.Fish 0.Quit:";cin >> choice;switch (choice){case 1:pAnimal = new Dog(5,Brown);break;case 2:pAnimal = new Horse(4, Black);break;case 3:pAnimal = new Fish(5);default:fQuit = true;break;}if (fQuit == false){pAnimal->Speak();pAnimal->Eat();pAnimal->Reproduce();pAnimal->Move();pAnimal->Sleep();delete pAnimal;cout << endl;}}//getchar();return 0;
}