virtualmethods.cpp

来自「《24学时精通c++》的光盘内容」· C++ 代码 · 共 28 行

 // Listing 18.1 - virtual methods
 #include <iostream>

 class Mammal
 {
 public:
     Mammal():itsAge(1) { std::cout << "Mammal constructor...\n"; }
     virtual ~Mammal() { std::cout << "Mammal destructor...\n"; }
     virtual void Speak() const { std::cout << "Mammal speak!\n"; }
 protected:
     int itsAge;
 };

 class Cat: public Mammal
 {
 public:
     Cat() { std::cout << "Cat constructor...\n"; }
     ~Cat() { std::cout << "Cat destructor...\n"; }
     void Speak()const { std::cout << "Meow!\n"; }
 };

 int main()
 {
     Mammal *pCat = new Cat;
     pCat->Speak();
     return 0;
 }