Sams Teach Yourself C++ in 21 Days

Implementing Inheritance 377

12

Mammal, assuming that these other classes all use public inheritance. Private inheritance is

discussed on Day 16, “Advanced Inheritance.”

Listing 12.2 demonstrates how to create objects of type Dogand then how to access the

data and methods of that type.

LISTING12.2 Using a Derived Object

1: //Listing 12.2 Using a derived object

2: #include <iostream>

3: using std::cout;

4: using std::endl;

5:

6: enum BREED { GOLDEN, CAIRN, DANDIE, SHETLAND, DOBERMAN, LAB };

7:

8: class Mammal

9: {

10: public:

11: // constructors

12: Mammal():itsAge(2), itsWeight(5){}

13: ~Mammal(){}

14:

15: //accessors

16: int GetAge() const { return itsAge; }

17: void SetAge(int age) { itsAge = age; }

18: int GetWeight() const { return itsWeight; }

19: void SetWeight(int weight) { itsWeight = weight; }

20:

21: //Other methods

22: void Speak()const { cout << “Mammal sound!\n”; }

23: void Sleep()const { cout << “shhh. I’m sleeping.\n”; }

24:

25: protected:

26: int itsAge;

27: int itsWeight;

28: };

29:

30: class Dog : public Mammal

31: {

32: public:

33:

34: // Constructors

35: Dog():itsBreed(GOLDEN){}

36: ~Dog(){}

37:

38: // Accessors

39: BREED GetBreed() const { return itsBreed; }

40: void SetBreed(BREED breed) { itsBreed = breed; }

41:

42: // Other methods