listr303.cpp

《21天学通C++》Teach Yourself C++ in 21 Days (Fourth Edition) 源代码

#include<iostream >
using namespace std;
class Animal
{
  public:
    virtual void Speak() { cout << "Animal Speaks" << endl; }
};

class Dog : public Animal
{
  public:
    void Speak() { cout << "Dog Speaks" << endl; }
};


class Cat : public Animal
{
  public:
    void Speak() { cout << "Cat Speaks" << endl; }
};

void DoIt(Animal*);

int main()
{

   Animal * pA = new Dog;
   DoIt(pA);
   return 0;
}

void DoIt(Animal * c)
{
   cout << "They passed some kind of  animal" << endl << endl;
   c->Speak();
}