CS Object oriented programming - Unit 1 - MCQs
UNIT I
Object oriented programming concepts – objects-classes- methods and
messages-abstraction and
encapsulation-inheritance- abstract classes- polymorphism.Introduction to C++-
objects- classes- constructors and destructors
1) 
Which of the following
language was developed as the first purely object
programming language?
a.
SmallTalk
b.
C++
c.
Kotlin
d.
Java
Answer: a. SmallTalk
Explanation: This programming language was invented
as the first pure OOPS (object-oriented) language. This language was
designed by Alan Kay in the early 1970s.
2. Who developed object-oriented programming?
a.
Adele Goldberg
b.
Dennis Ritchie
c.
Alan Kay
d.
Andrea Ferro
Answer: c. Alan Kay
Explanation: In the year 1970, Alan Kay gave Object-Oriented
programming. He coined the concept of
OOPS at a grad school in the year 1966 or 1967. Alan kay, Adele Goldberg, Dan Ingalls
and others developed
the first Smalltalk programming language,
which follows the OOPS concept.
3. Which of the following is not an OOPS concept?
a.
Encapsulation
b.
Polymorphism
c.
Exception
d.
Abstraction
Answer: c. Exception
4. Which feature of OOPS described the reusability of code?
a.
Abstraction
b.
Encapsulation
c.
Polymorphism
d.
Inheritance
Answer: d. Inheritance
Explanation: Inheritance is the feature of OOPS, which allows
the users of OOPS to reuse the code
which is already written. This OOPS feature inherits the features of another
class in the programs. This mechanism actually
inherits the fields
and methods of the
superclass.
5. Which of the following
language supports polymorphism but not the classes?
a.
C++ programming language
b.
Java programming language
c.
Ada programming language
d.
C# programming language
Answer: c. Ada programming language
Explanation: It is a programming language
that disapproves of the concept
of polymorphism but supports the concept of classes. It
is an object-based language. So, it does not follow the Object-oriented programming
concepts.
6. Which among the following feature is not in the general definition of OOPS?
a.
Modularity
b.
Efficient Code
c.
Code reusability
d.
Duplicate or Redundant
Data
Answer: d. Duplicate or Redundant Data
Explanation: Duplicacy or Redundancy of data is a
feature which totally dependent on the programmers. So, it cannot be created by the OOPS.
7. Which feature of OOPS derives
the class from another class?
a.
Inheritance
b.
Data hiding
c.
Encapsulation
d.
Polymorphism
Answer: a. Inheritance
Explanation: Inheritance is an important
OOPS feature which derives the class from the base class
or superclass. This OOPS feature inherits the features of another class in the
programs. This mechanism actually
inherits the fields and methods of the superclass.
8. Define the programming language, which does not support
all four types of inheritance?
a.
Smalltalk
b.
Kotlin
c.
Java
d.
C++
Answer: c. Java
Explanation: Java is a programming language that disapproves of the
concept of 'multiple inheritance'. So, it does not agree with all types of inheritance. But, we can implement 'multiple inheritance' in Java language
using the interface concept
9. A single program of OOPS
contains classes?
a.
Only 1
b.
Only 999
c.
Only 100
d.
Any number
Answer: d. Any number
Explanation: We can define any number of classes with different names in a single program
of OOPS.
10. Which operator from the following can be
used to illustrate the feature of polymorphism?
a.
Overloading <<
b.
Overloading &&
c.
Overloading | |
d.
Overloading +=
Answer: a. Overloading <<
Explanation: << is an insertion
operator which is used for overloading (polymorphism).
11. Which two features of object-oriented programming are the same?
a.
Abstraction and Polymorphism features are the same
b.
Inheritance and Encapsulation features are the same
c.
Encapsulation and Polymorphism features are the same
d.
Encapsulation and Abstraction
Answer: d.
Encapsulation and Abstraction
Explanation: Encapsulation and Abstraction are the same OOPS concepts.
Encapsulation hides the features of the object and binds all the properties inside
a single class. And abstraction is a feature
that shows the required
data to the user.
12. Which header file is required
by the C++ programming language
to use the OOPS concept?
a.
stdio.h
b.
iostream.h
c.
stdlib.h
d.
We can easily use the OOPS concepts
in c++ programs without using any header file.
Answer: d.
We can easily use the OOPS concepts
in c++ programs without using any header file.
Explanation: There is no need to use any particular header
file for using the OOPS concept in the
C++ programs. The C++ functions and variables have their respective header
files, which should be defined
in the program.
13.
Which of the following is not correct
for virtual function
in C++ ?.
A. Virtual function
can be static.
B. Virtual function
should be accessed
using pointers
C. Virtual function
is defined in base class
D. Must be declared in public section
of class
Ans : A
Explanation: Virtual function
is can’t be static in C++.
14. How can we make a class
abstract?
A. By declaring it abstract using the static keyword
B. By declaring it abstract using the virtual
keyword.
C. By making
at least one member function as pure virtual function
D. By making
all member functions
constant
Ans : C
Explanation: We can make a class abstract
by making at least one member function
as pure virtual function.
15. How many specifiers are present in access specifiers in class?
A. 2
B. 1
C. 4
D. 3
Ans : D
Explanation: There are three types
of access specifiers. They are public,
protected and private.
16.
Which of these following members
are not accessed by using direct member
access operator?
A. Public
B. Private
C. Protected
D. Both B & C
Ans : D
Explanation: Because of the access
is given to the private
and protected, We can’t access them by using direct member access
operator.
17. Which other
keywords are also used to declare the class other
than class?
A. Struct
B. Union
C. Object
D. Both struct
& union
Ans : D
Explanation: Struct and union take the same definition of class but differs in the access
techniques.
18. Which of the
following is true?
A. All objects
of a class share all data members
of class
B. Objects of a class do not share non-static members. Every object
has its own copy
C. Objects of a class do not share codes of non-static methods, they have their own copy
D. None of these
Ans : B
Explanation: very object maintains a copy of non-static data members. For example, let Student be a class with data members as name,
year, batch. Every object of student will have its own name, year and batch. On a side note, static data members are
shared among objects. All objects share
codes of all methods
19. Which of the
following can be overloaded?
A. Object
B. Operators
C. Both A & B
D. None of the above
Ans : C
Explanation: Object
and Operators can be overloaded.
20.
Which is also called as abstract class?
A. Virtual function
B. Derived class
C. Pure virtual
function
D. None of the mentioned
Ans : C
Explanation: Classes that contain at least one pure virtual
function are called
as abstract base classes.
21.
What will be the output of the following program? #include
<iostream>
using namespace std; class LFC
{
static int x; public:
static void Set(int
xx)
{
x = xx;
}
void Display()
{
cout<< x ;
}
};
int LFC::x = 0; int main()
{
LFC::Set(33);
LFC::Display(); return
0;
}
A.
The program will print the output 0.
B. The program
will print the output 33.
C. The program will print the output Garbage.
D. The program
will report compile
time error.
Ans : D
Explanation: The program
will report compile time error: cannot call member function "void LFC::Display()" without object
21. What will be the output of the following program?
Note:Includes all required
header files class
course
{
int x, y; public: course(int xx)
{
x = ++xx;
}
void Display()
{
cout<< --x << "
";
}
};
int main()
{
course obj(20); obj.Display();
int *p =
(int*)&obj ;
*p = 5; obj.Display(); return 0;
}
A. 20 4
B. 21 4
C. 20 5
D. 21 5
Ans : A
Explanation: 20 4 will be the
output of the following program
22.
In a class, member variables
are often called its , and its member functions are sometimes referred
to as its behaviour, or .
1.
attributes, methods
2. none of these
3. values, morals
4. data, activities
5. attributes, activities
Answer: (1)
23.Which of these keywords
are access specifiers?
1.
near and far
2.
opened and closed
3. table and row
4. none of these
5. private and public
Answer: (5)
24. Use of protects data from inadvertent modifications.
1.
protect() member function
2. private access specifier
3. class protection operator, @
4. none of these
5. public access
specifier
Answer: (2)
25. Which is private member functions access
scope?
a) Member functions which can only be used within
the class
b)
Member functions which
can used outside
the class
c) 
Member functions which are accessible in derived class
d) Member functions
which can’t be accessed inside the class
Answer: a
Explanation: The member
functions can be accessed inside the class only if they are private. The access is scope is limited to ensure the security of the private
members and their
usage.
26.
Which among the following is true?
a)
The private members
can’t be accessed
by public members
of the class
b) The private members
can be accessed by public members of the class
c) The private
members can be accessed only by the private members
of the class
d) The private members
can’t be accessed by the
protected members of the class
Answer: b
Explanation: The private
members are accessible within the class.
There is no restriction on use of private members by public or
protected members. All the members can access the private member
functions of the class.
27.
Which member can never be accessed by inherited classes?
a)
Private member function
b) Public member
function
c) Protected member
function
d)
All can be accessed
Answer: a
Explanation: The private member functions can never be accessed in
the derived classes. The access specifiers is of maximum
security that allows
only the members
of self class to access
the private member functions.
28.
Which syntax among the following
shows that a member is private in a class?
a)
private: functionName(parameters)
b) 
private(functionName(parameters))
c) private functionName(parameters)
d) private::functionName(parameters)
Answer: c
Explanation: The function
declaration must contain
private keyword follower
by the return type and function name. Private keyword
is followed by normal
function declaration.
29.
If private member functions are to be declared in C++
then
a)
private: <all private
members>
b) private <member name>
c) private(private member
list)
d) private :- <private members>
Answer: a
Explanation: The private members
doesn’t have to have the keyword with each private member. We only have to specify the keyword private
followed by single colon
and then private
member’s are listed.
30. In java, which rule must be followed?
a) Keyword private
preceding list of private member’s
b) Keyword private
with a colon before
list of private member’s
c) Keyword private
with arrow before each
private member
d) Keyword private
preceding each private
member
Answer: d
Explanation: The private
keyword must be mentioned before
each private member.
Unlike the rule in C++ to specify private once and
list all other private member’s, in java all member declarations must be preceded by the keyword private.
31. 
How many private
member functions are allowed in a class?
a) Only 1
b) Only 7
c) Only 255
d) As many as required
Answer: d
Explanation: There are no conditions applied on the number of
private member functions that can be declared
in a class. Though the system may restrict use of too many functions
depending on memory.
32. How to access a private member
function of a class?
a) Using object of class
b) Using object pointer
c)
Using address of member function
d) Using class address
Answer: c
Explanation: Even the private
member functions can be called
outside the class.
This is possible
if address of the function is known. We can use the address to call the
function outside the class.
33. Private member
functions
a) Can’t be called from enclosing class
b) Can be accessed from enclosing class
c) Can be accessed only if nested
class is private
d) Can be accessed only if nested
class is public
Answer: a
Explanation: The nested class members
can’t be accessed in the enclosed class even though other members can be accessed. This is to ensure the class
members security and not to go against the rules of private members.
34. Which function among the following can’t be accessed
outside the class in java in same
package?
a) public void show()
b) void show()
c)
protected show()
d) static void show()
Answer: c
Explanation: The protected
members are available within the class. And are also available in derived
classes. But these
members are treated
as private members
for outside the class and inheritance structure. Hence can’t be accessed.
35. If private members are to be called outside
the class, which
is a good alternative?
a) Call a public member function which calls private
function
b) Call a private member
function which calls private function
c)
Call a protected member
function which calls private function
d) Not possible
Answer: a
Explanation: The private member functions can be accessed
within the class.
A public member
function can be called which in turn calls the private member function.
This maintains the security and adheres to the rules of private
members.
36. If a function in java is declared private
then it
a) Can’t access the standard
output
b) Can access the standard
output
c) Can’t access any output
stream
d) 
Can access only the output
streams
Answer: b
Explanation: The private members
can access any standard input or output. There is no restriction on access
to any input or output
stream. And since standard input
can also be used hence
only accessing the output stream is
not true.
37. Which among the following best describes abstract
classes?
a) If a class has more than one
virtual function, it’s abstract class
b) If a class have only one pure virtual
function, it’s abstract
class
c) If a class has at least one pure virtual function,
it’s abstract class
d) If a class has all the pure virtual
functions only, then it’s abstract
class
Answer: c
Explanation: The condition for a class to be called abstract
class is that it must have at least one pure virtual
function. The keyword
abstract must be used while
defining abstract class in java.
38. Can abstract class have main() function
defined inside it?
a) Yes, depending on return
type of main()
b) Yes, always
c) No, main must not be defined inside abstract class
d) No, because main() is not abstract function
Answer: b
Explanation: This is a property of abstract class. It can define main()
function inside it. There is no restriction on its
definition and implementation.
39. If there is an abstract
method in a class
then, _
a) Class must be abstract
class
b) Class may or may not be abstract class
c)
Class is generic
d) Class must be public
Answer: a
Explanation: It is a rule that if
a class have even one abstract method, it must be an abstract class. If this rule was not made, the abstract
methods would have got skipped to get defined in some places which are undesirable with the idea of abstract class.
40.
If a class is extending/inheriting another
abstract class having abstract method,
then
 |
a) Either implementation of method or making class
abstract is mandatory
b) Implementation of the method
in derived class is mandatory
c) Making the derived class also abstract
is mandatory
d) It’s not mandatory to implement the abstract method of parent class
Answer: a
Explanation:
Either of the two things must be done, either implementation or declaration of class as
abstract. This is done to ensure that the method intended to
be defined by other classes gets defined at every
possible class.
41.
Abstract class A has 4 virtual functions. Abstract class B defines only
2 of those member functions as it
extends class A. Class C extends class B and implements the other two member functions
of class A. Choose
the correct option below.
a) Program won’t
run as all the methods
are not defined by B
b) Program won’t run as C is not inheriting A directly
c) Program won’t run as multiple inheritance is used
d) Program runs correctly
Answer: d
Explanation: The program runs correctly. This is because even class B is
abstract so it’s not mandatory to
define all the virtual functions. Class C is not abstract but all the virtual
functions have been implemented will that class.
42. Abstract classes can instances.
a) Never have
b) Always have
c) Have array of
d) Have pointer of
Answer: a
Explanation:
When an abstract class is defined, it
won’t be having the implementation of
at least one function. This will
restrict the class to have any constructor. When the class doesn’t have constructor, there won’t be any instance
of that class.
43. We to an abstract class.
a) Can create pointers
b) Can create references
c) Can create pointers or references
d) Can’t create any reference, pointer or instance
Answer: c
Explanation:
Even though there can’t be any instance of abstract class. We can always create pointer or reference to abstract class.
The member functions which have some implementation inside abstract itself
can be used with these
references.
44. Which among the following is an important use of abstract
classes?
a) Header files
b) Class Libraries
c) Class definitions
d) Class inheritance
Answer: b
Explanation:
The abstract classes can be used to create a generic, extensible class library
that can be used by other
programmers. This helps us to get some already implemented codes and functions
that might have not been provided by the programming language itself.
45. Can abstract classes have static methods (Java)?
a) Yes, always
b) Yes, but depends on code
c) No, never
d) No, static members can’t have different values
Answer: a
Explanation: There is no restriction on declaring static methods. The only condition
is that the virtual functions must have some definition in the program.
46.
Encapsulation helps in writing classes in java a.Mutable
b.Abstract c.Wrapper
d.Immutable Answer: (d)
47.
Which among the following should
be encapsulated? a.The
data which is prone to change is near future
b.The data prone
to change in long terms c.The data
which is intended to be changed d.The data which belongs
to some other class
Answer: (a)
48.
How can Encapsulation be achieved? a.Using
Access Specifiers
b.Using only private members
c.Using inheritance
d.Using Abstraction
Answer: (a)
49.
Which among the following violates
the principle of encapsulation almost always? a.Local
variables
b.Global variables
c.Public variables d.Array
variables Answer: (b)
50. Which among the following
would destroy the encapsulation mechanism if it was allowed in programming?
a.Using access
declaration for private members of base class
b.Using access declaration for public members of base class c.Using
access declaration for local variable
of main() function
d.Using access declaration for global
variables
Answer: (a)
51. Which among the following can be a concept against
encapsulation rules? a.Using
function pointers
b.Using char* string
pointer to be passed to non-member function
c.Using object array
d.Using any kind of pointer/array address
in passing to another function
Answer: (d)
52. Consider the following code and select the correct
option: class student
{
int marks;
public : int* fun()
{
return &marks;
}
};
main()
{
student s;
int *ptr=c.fun(); return 0;
}
a.This code is good to go
b.This code may result
in undesirable conditions c.This code will generate error
d.This code violates
encapsulation
Answer: (d)
53.
Consider the code and select the wrong choice: class
hero
{
char name[10]; public
: void disp()
{
cout<<name;
}
};
a.This maintains encapsulation
b.This code doesn’t maintain
encapsulation c.This code is vulnerable
d.This code gives error
Answer: (a)
54. Encapsulation is the way to add functions in a
user defined structure. a.True
b.False c.May be
d.Can't say Answer: (b)
55. Using encapsulation data security
is
a.Not ensured
b.Ensured to some extent
c.Purely ensured d.Very low Answer: (b)
56. How can you make the private
members inheritable?
a) By making their visibility mode as public
only
b) By making their visibility mode as protected
only
c) By making their visibility mode as private
in derived class
d) It can be done both by making the visibility mode public or protected
Answer: d
Explanation: It is not mandatory that you have to make the visibility
mode either public or protected. You
can do either of those. That will give you permission to inherit the private members
of base class.
57. If a derived class object is created, which constructor is called
first?
a) Base class constructor
b) Derived class constructor
c) Depends on how we call the object
d) Not possible
Answer: a
Explanation:
First the base class constructor is invoked. When we create a derived class
object, the system tries to invoke
its constructor but the class is derived so first the base class must be initialized, hence in turn the base class constructor is invoked before the derived
class constructor.
58. Members which
are not intended to be
inherited are declared as
a) Public members
b) Protected members
c) Private members
d) Private or Protected members
Answer: c
Explanation: Private access specifier is the most secure access mode. It
doesn’t allow members to be inherited. Even Private inheritance can only inherit protected and public members.
59. If a base class is inherited in protected access mode then which among the following is true?
a) Public and Protected members
of base class becomes protected members of derived
class
b) Only protected members become protected members of derived
class
c) Private, Protected
and Public all members
of base, become private
of derived class
d) Only private members of base,
become private of derived class
Answer: a
Explanation:
As the programming language rules apply, all the public and protected members
of base class becomes protected
members of derived class in protected access mode. It can’t be changed
because it would
hinder the security
of data and may add vulnerability in the program.
60. Which is the correct
syntax of inheritance?
a) class derived_classname : base_classname{ /*define class body*/
};
b) class base_classname : derived_classname{ /*define class body*/
};
c) class derived_classname : access
base_classname{ /*define class body*/ };
d) class base_classname :access derived_classname{ /*define class body*/ };
Answer: c
Explanation:
Firstly, keyword class should come, followed by the derived class name. Colon
is must followed by access in which
base class has to be derived, followed by the base class name. And finally
the body of class. Semicolon after the body is also must.
61. Which one is the best description of polymorphism?
A. It is the ability
for undefined message/data to be processed in at least
one way
B.
It is the ability for a message/data to be processed
in more than one form
C. It is the ability
for many messages/data to be processed
in many ways
D. none of these
Ans: B
62. The languages that support
classes but not polymorphism is called?
A. child Class-based language
B. Class-based language
C. Object-based language
D. Procedure Oriented
language
Ans: C
63. Which one is the language that does not support polymorphism but support classes?
A.C#
b)
Ada
c) C++
d)
Java
Ans: B
64. The feature that its specification is if same message is passed to objects of several different
classes and all of those can respond in a different
way then it is
called?
A. Inheritance
B. Classes
C. Polymorphism
D. none of these
Ans: C
65. Which type of function
shows polymorphism among
the following?
A. Inline function
B.
Virtual function
C. Undefined functions
D. Class member functions
Ans: B
66. In case of using abstract class or function
overloading, the function is supposed
to be called first?
A. Local function
B. Function with the
highest priority in the compiler
C. Global function
D. none of these
Ans: B
67. Which one of the following can’t be used for polymorphism?
A. Member functions overloading
B. Static member functions
C. global member
function
D. Constructor overloading
Ans: B
68. Which one of the following can show polymorphism?
A. Overloading ||
B. Overloading &&
C. Overloading <<
D.Overloading +=
Ans: C
69. What is the difference between struct and class in C++?
(A)
All members of a structure
are public and structures don’t have constructors and destructors
(B) Members of a class are
private by default and members of struct are public by default. When deriving a struct from a
class/struct, default access-specifier for a base class/struct is public and when deriving
a class, default access
specifier is private.
(C) All members of a structure
are public and structures don’t have virtual
functions
(D) All of the above
Answer: (B)
70. Constructor is executed when .
A. An object goes out of scope.
B. A class is declared
C. An object is created
D. An object is used
Ans : C
Explanation: Constructor is executed when An object
is created.
71. How many ways of reusing are there
in class hierarchy?
A. 1
B. 3
C. 4
D. 2
Ans : D
Explanation: Class hierarchies promote reuse in two ways. They are code sharing and interface
sharing.
72. Where does the object is created?
A. Class
B. Constructor
C. Destructors
D. Attributes
Ans : A
Explanation: In class, only all the listed items except class
will be declared.
73. Which of the following
is a valid class declaration?
A. Class A { int x; };
B. Class B { }
C. Public class
A { }
D. Object A { int x; };
Ans : A
Explanation: Class A { int x; };
is a
valid class declaration.
74.
Which of the following is not correct (in C++) ?i)
Class templates and function templates are instantiated
in the same way ii) Class templates differ from function templates in the way
they are initiated iii) Class
template is initiated by defining an object using the template argument iv) Class
templates are generally used for storage classes.
A. i
B.
i & ii
C. ii ,iii, iv
D. iv
Ans : C
Explanation: In C++ class template and function template
are similar in the way the are initiated.
Class template are not used for storage class. Class templates and function
templates are instantiated in the
same way and Class template is not initiated by defining an object using the template.
So (2), (3), (4) are not correct in C++.
75. Which of the following
keywords is used to control
access to a class member?
A. Default
B. Break
C. Protected
D. Asm
Ans : C
Explanation: Protected
keywords is used to control
access to a class member
76. Which of the following statements is incorrect?
A. Destructor of base class
should always be static
B. Destructor of base class should always be virtual.
C. Destructor of base class should not be
virtual.
D. Destructor of base class should always
be private.
Ans : B
Explanation: Destructor of base class should always
be virtual statements is incorrect
77. Which operator can not be overloaded?
A. +
B. ::
C. -
D.
*
Ans : B
Explanation: :: operator can not be overloaded
78. When Virtual Table is created?
A. Every Class has VTable
B. Class inherited from other Class
C. Class has atleast one Virtual Function
D. When a Class Overrides
the function of Base class
Ans : C
Explanation: When Virtual Table is created
Class has atleast
one Virtual Function
79. What is the size of empty class?
A. 0
B. 2
C. 4
D. 1
Ans : D
Explanation:
When we create object of empty class at that time State of that object is
nothing. Behaviour of that object is
also nothing, but compiler assigns a unique address to that object. Memory in Computer is always organized in
the form of bytes and minimum memory available
at object address
location is 1 byte.
That's why size of object of empty class is 1 byte.
80. Which of the followings is/are automatically added to every
class, if we do not write our own.
A. Copy Constructor.
B. Assignment Operator
C. A constructor without any parameter
D. All of the above
Ans : D
Explanation: In C++, if we do not write our own, then compiler
automatically creates a default constructor, a copy constructor and a assignment operator for every class..
81. Which of the following gets called when an
object is being created?
A. Constuctor
B. Virtual Function
C. Destructors
D. Main
Ans : A
Explanation: Virtual
Function gets called
when an object is being
created.
82. Destructor has a
same name as the constructor and it is preceded by?
A.
!
B. ?
C. ~
D. $
Ans : C
Explanation: Destructor has a same name as the constructor and it is preceded by ~.
83. Like constructors, can there be more than one destructors in a class?
A.
Yes
B. No
C.
May Be
D. Can't Say
84.
State whether the following statements about the constructor are True or False. i) constructors should be declared
in the private section. ii) constructors are invoked automatically when the objects are created.
A.
True,True
B. True,False
C.
False,True
D. False,False
Ans : C
Explanation: Statement
1 is false and statement
2 is true.
85. Which of the following is true about constructors.
i) They cannot be virtual
ii) They cannot be private.
iii) They are automatically called
by new operator.
A. All i,ii,iii
B. i & iii
C. ii & iii
D. i & ii
Ans : B
Explanation: i) True: Virtual constructors don't make sense, it is meaningless to the C++ compiler to create an object polymorphically. ii) False: Constructors can be private
86.
Destructors for automatic objects if the program terminates with a call to function exit or function
abort
A. Are called
B.
Are not called
C. Are inherited
D. Are created
Ans : B
Explanation: Destructors Are not called for automatic
objects if the program terminates with a call
to function exit or function
abort
87. Which contructor function is designed to copy object of same class type?
A. Copy constructor
B. Create constructor
C. Object constructor
D. Dynamic constructor
Ans : A
Explanation: Copy constructor function
is designed to copy object of same class type.
88.
What will be the output of the following program? #include <iostream>
using namespace std; class LFC
{
int id;
static int count; public:
LFC() {
count++; id = count;
cout << "constructor for id " <<
id << endl;
}
~LFC() {
cout << "destructor
for id " << id << endl;
}
};
int LFC::count = 0; int main() {
LFC a[3];
return 0;
}
A. constructor for id 1 constructor for id 2 constructor for id 3 destructor for id 3 destructor for id 2 destructor for id 1
B. constructor for id 1 constructor for id 2 constructor for id 3 destructor for id 1 destructor for id 2 destructor for id 3
C. Compiler Dependent
D. constructor for id 1 destructor
for id 1 Ans : D
Explanation:
In the above program, id is a static variable and it is incremented with every
object creation. Object a[0] is
created first, but the object a[2] is destroyed first. Objects are always destroyed in reverse order of their
creation. The reason for reverse order is, an object created later may
use the previously created object.
89.
What will be the output of the following program? #include <iostream>
using namespace std; class LFC {
LFC() { cout <<
"Constructor called"; }
};
int main()
{
LFC t1;
return 0;
}
A. Compiler Error
B. Runtime Error
C.
Constructor called
D. destructor for id 1
Ans : A
Explanation: By default all members of a class are private. Since no access specifier is there for find(), it becomes private and it is called outside the class when t1 is construct
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