Sams Teach Yourself C++ in 21 Days

43:

44: private:

45: BREED itsBreed;

46: };

47:

48: Mammal::Mammal():

49: itsAge(3),

50: itsWeight(5)

51: {

52: std::cout << “Mammal constructor... “ << endl;

53: }

54:

55: Mammal::~Mammal()

56: {

57: std::cout << “Mammal destructor... “ << endl;

58: }

59:

60: Dog::Dog():

61: itsBreed(GOLDEN)

62: {

63: std::cout << “Dog constructor... “ << endl;

64: }

65:

66: Dog::~Dog()

67: {

68: std::cout << “Dog destructor... “ << endl;

69: }

70: int main()

71: {

72: Dog Fido;

73: Fido.Speak();

74: Fido.WagTail();

75: std::cout << “Fido is “ << Fido.GetAge() << “ years old” << endl;

76: return 0;

77: }

Mammal constructor...

Dog constructor...

Mammal sound!

Tail wagging...

Fido is 3 years old

Dog destructor...

Mammal destructor...

Listing 12.3 is like Listing 12.2, except that on lines 48 to 69 the constructors

and destructors now print to the screen when called. Mammal’s constructor is

called, then Dog’s. At that point, the Dogfully exists, and its methods can be called.

OUTPUT

380 Day 12

LISTING12.3 continued

ANALYSIS