Question

1 #include <string>

2 #include <iostream>

3 using std::string;

4 using std::cout;

5 using std::endl;

7 class Pet

8 {

9   public:

10       string name;

11       virtual void print( ) const;

12};

13

14 class Dog:public Pet

15 {

16   public:

17       string breed;

18       virtual void print( ) const;

19};

20

21 int main( )

22 {

23   Dog vdog;

24   Pet vpet;

25   vdog.name = "Tiny";

26   vdog.breed = "Great Dane";

27   vpet = vdog;

28   vpet.print( );

29

30   Pet *ppet;

31   ppet = new Pet;

32   Dog *pdog;

33   pdog = new Dog;

34   pdog->name = "Tiny";

35   pdog->breed = "Great Dane";

36   ppet = pdog;

37   ppet->print();

38   pdog->print();

39

40   return 0;

41 }

42

43 void Dog::print( )const

44 {

46   cout << "breed: "<< breed <<endl;

47 }

48

49 void Pet::print() const

50 {

51   cout << "name: " << name << endl;

52 }

ANSWER THESE QUESTIONS

What is the base class called? ___________________________________

What is the derived class called? _________________________________

Are lines 11 and 18 a pure virtual function? How can you tell? __________

____________________________________________________________

What does lines 23-28 demonstrate? _______________________________

_____________________________________________________________

What does lines 30-38 demonstrate? _______________________________

_____________________________________________________________

Which example (lines 23-28 or line 30-38) is better to use? Why? _________

______________________________________________________________

What is the -> used for? ___________________________________________

Define virtual function. ___________________________________________

_______________________________________________________________

What does line 14 tell you? _________________________________________

T/ F If a derived class is virtual, then the base class is automatically virtual. ___

Answer 1

1) Class Pet is a Based Class.

2) Class Dog is Derived Class because it is child class which inherited from parent based class Pet

3)yes line number 11 and 18 are pure virtual function because

virtual void print() const; declared in Base Class and Also in child class

4) line no 23 to 28

Class Dog Creates the Object named as vdog

Class Pet Creates the Object named as vpet

vdog.name="Tiny" Here object name vdog access the name variable with value Tiny

vdog.breed="Great Dane"... Here object name vdog access the name variable breed with value Great Dane

vpet=vdog Here object vdog assign to vpet and After that call vpet object

5) Pet * ppet; // declare pointer object

ppet=new Pet; // creates Object ppet

Dog *pdog ; // declare pointer object with name *pdog

pdog=new Dog; // creates Object pdog

6) lines 23 to 28 is easy to used beacuase you directly used object with variable name

7) -> that point value to objects reference

8) virtual function ===

virtual void print()

Virtual function is a member function that u expect to redefined in derived class so when you refer derived class object using point or reference to the base class you can call virtual funcion for the object

9)

line 14 ::class Dog:public Pet

Class Dog It Inherits the class Pet so Class Dog access the method and properties of Pet class.

10) yes that becomes virtual