list1202.cpp

teach yourself C++ in 21 days 第五版

//Listing 12.2 Using a derived object
#include <iostream>
using std::cout;
using std::endl;
      
enum BREED { GOLDEN, CAIRN, DANDIE, SHETLAND, DOBERMAN, LAB };
       
class Mammal
{
  public:
    // constructors
    Mammal():itsAge(2), itsWeight(5){}
    ~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():itsBreed(GOLDEN){}
    ~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;
};

int main()
{
   Dog Fido;
   Fido.Speak();
   Fido.WagTail();
   cout << "Fido is " << Fido.GetAge() << " years old" << endl;
   return 0;
}