Deck 14: Inheritance

Question 1

If class D is derived from class B,then we say that class D inherits from class B.

Answer 1

True

Question 2

An object of a derived class type has exactly one type,the type with which it was declared.

Answer 2

False

Question 3

If B is a base class of D,then D's members cannot access the private data members of B without regard to the kind of inheritance.

Answer 3

True

Question 4

If class D is derived from class B then class D has only some of the members from B,and the additional members defined in D.

Question 5

If B is a public base class of D,then D's members cannot invoke public members functions of B.

Question 6

A programmer must have the source code for libraries to extend them,even using inheritance.

Question 7

You never put a declaration of an inherited member in the derived class.

Question 8

If a base class constructor is not called explicitly in the definition of a derived class constructor,an error results.

Question 9

We can assign a base class object to a derived class variable.

Question 10

If B is a base class of D,then D's members cannot invoke private member functions of B without regard to the kind of inheritance.

Question 11

A base/member initialization list is preceded by

A)two colons
B)a dot (or period)
C)a single colon
D)a semicolon

Question 12

Constructors are inherited.After all something has to initialize the inherited variables.

Question 13

If class D is derived from class B,we speak of D as the derived class and B as the base class.

Question 14

An inheritance chain of any desired length is possible.

Question 15

A programmer can use inheritance with an existing library for which only the header file and binary are available,to derive a class more suitable to her purpose.

Question 16

Deriving a class from a base class requires serious changes to the base class.

Question 17

The class D inherits from base class B using public inheritance.The class B has public member function f(),but the derived class has no function member with this signature.The f()is not available to an object of class D.

Question 18

In C++,inheritance has much to do with the gene pool.Explain.

Question 19

When class D is derived from class B,the derived class is usually smaller.Explain.

Question 20

If class D is derived from class B,we speak of D as the child class and B as the parent class.

Question 21

Which of the following is correct syntax to declare C++ class B to be a public base class for derived class D

A)public base class B: class D {/*…*/};
B)class D : public class B {/* … */};
C)class D : public B {/* … */};
D)class B: public D { };
E)None of the above

Question 22

Suppose class Child is derived from class Parent that was in turn derived from class GrandParent.When we destroy an object of class Child,three destructors are called: i)Child,ii)Parent,iii )GrandParent..What is the order?

A)Child,Parent,GrandParent
B)Parent,GrandParent,Child
C)GrandParent,Child,Parent
D)GrandParent,Parent,Child
E)GrandParent,Child,Parent

Question 23

Given the class below,tell to what value the default constructor initializes the data member.Name this initialization technique and give another way to write the constructor.
class A
{
public:
A();
private:
int a;
};
A::A(): a(17)
{
//deliberately empty
}

Question 24

Suppose class Child is derived from class Parent that was in turn derived from class GrandParent.This question concerns order of calls to constructors and destructors for these three classes.Declare an object of class Child.We know that Child,Parent and GrandParent constructors are called.In what order are these constructors are called? When the time comes to destroy the class Child object,we know that Child,Parent and GrandParent destructors are called.In what order are these destructor called?

Question 25

In the code for HourlyEmployee that is derived from Employee,the constructor code appears
HourlyEmployee::
HourlyEmployee(string theName,
string theNumber,
double theWageRate,
double theHours
)
: Employee(theName,theNumber),
wageRate(theWageRate),
hours(theHours)
{
// deliberately empty
}
Describe the purpose of the items after the colon (:)in this code.

Question 26

What are the benefits of inheritance and Object Oriented Programming?

Question 27

When a derived class inherits from a base class,how is the base class constructor called?

Question 28

Suppose class Child is derived from class Parent that was in turn derived from class GrandParent.When we declare an object of class Child,three constructors are called: i)Child,ii)Parent,iii )GrandParent..What is the order?

A)Child,Parent,GrandParent
B)Parent,GrandParent,Child
C)GrandParent,Child,Parent
D)GrandParent,Parent,Child
E)GrandParent,Child,Parent

Question 29

If a class B is a pubic base class for a derived class D,then an object of class D bears what relationship to class B?

A)A has-a relationship.
B)A fraternal relationship
C)An is-a relationship.
D)There is no relationship here.

Question 30

Neither the assignment operator overloading nor the copy constructor is inherited.If you do not create one,does this mean that the derived class will have no assignment operator or copy constructor?