ptrtomember.cpp

24学时攻克C++光盘源代码 深入浅出 方便实用

 //Listing 20.9 Pointers to member functions 
 #include <iostream>
 
 enum BOOL {FALSE, TRUE};
 
 class Mammal
 {
 public:
     Mammal():itsAge(1) {  }
     virtual ~Mammal() { }
     virtual void Speak() const = 0;
     virtual void Move() const = 0;
 protected:
     int itsAge;
 };
 
 class Dog : public Mammal
 {
 public:
     void Speak()const { std::cout << "Woof!\n"; }
     void Move() const { std::cout << "Walking to heel...\n"; }
 };
 
 class Cat : public Mammal
 {
 public:
     void Speak()const { std::cout << "Meow!\n"; }
     void Move() const { std::cout << "slinking...\n"; }
 };
 
 class Horse : public Mammal
 {
 public:
     void Speak()const { std::cout << "Winnie!\n"; }
     void Move() const { std::cout << "Galloping...\n"; }
 };
 
 int main()
 {
     void (Mammal::*pFunc)() const =0;
     Mammal* ptr =0;
     int Animal;
     int Method;
     bool fQuit = false;
 
     while (fQuit == false)
     {
         std::cout << "(0)Quit (1)dog (2)cat (3)horse: ";
         std::cin >> Animal;
         switch (Animal)
         {
         case 1: 
             ptr = new Dog; 
             break;
         case 2: 
             ptr = new Cat; 
             break;
         case 3: 
             ptr = new Horse; 
             break;
         default: 
             fQuit = true; 
             break;
         }
         if (fQuit)
             break;
 
         std::cout << "(1)Speak  (2)Move: ";
         std::cin >> Method;
         switch (Method)
         {
         case 1: 
             pFunc = Mammal::Speak; 
             break;
         default: 
             pFunc = Mammal::Move; 
             break;
         }
 
         (ptr->*pFunc)();
         delete ptr;
     }
     return 0;
 }