Programming In C++ Solved MCQs

Programming In C++ MCQs

This section contains more frequently asked Programming In C++ MCQs in the various University Level and Competitive Examinations.

Practice it now to sharpen your concepts and knowledge

1.The address of a variable temp of type float is

*temp
&temp
float& temp
float temp&

B. &temp

2.What is the output of the following code char symbol[3]={‘a’,‘b’,‘c’}; for (int index=0; index<3; index++) cout << symbol [index];

a b c
“abc”
abc
‘abc’

C. abc

3.The process of building new classes from existing one is called ______.

Polymorphism
Structure
Inheritance
Cascading

C. Inheritance

4.If a class C is derived from class B, which is derived from class A, all through public inheritance, then a class C member function can access

protected and public data only in C and B.
protected and public data only in C.
private data in A and B.
protected data in A and B.

D. protected data in A and B.

5.If the variable count exceeds 100, a single statement that prints “Too many” is

if (count<100) cout << “Too many”;
if (count>100) cout >> “Too many”;
if (count>100) cout << “Too many”;
None of these

C. if (count>100) cout << “Too many”;

6.Usually a pure virtual function

has complete function body.
will never be called.
will be called only to delete an object.
is defined only in derived class.

D. is defined only in derived class.

7.To perform stream I/O with disk files in C++, you should

open and close files as in procedural languages
use classes derived from ios
use C language library functions to read and write data.
include the IOSTREAM.H header file.

B. use classes derived from ios

8.Overloading the function operator

requires a class with an overloaded operator.
requires a class with an overloaded [ ] operator.
allows you to create objects that act syntactically like functions
usually make use of a constructor that takes arguments.

A. requires a class with an overloaded operator.

9.If x = y,5 = 2 then x ∧ y equals________. (where ∧ is a bitwise XOR operator)

00000111
10000010
10100000
11001000

A. 00000111

1.If an array is declared as int a[4] = {3, 0, 1, 2}, then values assigned to a[0] & a[4] will be ________

3, 2
0, 2
3, 0
0, 4

C. 3, 0

2.Mechanism of deriving a class from another derived class is known as____

Polymorphism
Single Inheritance
Multilevel Inheritance
Message Passing

C. Multilevel Inheritance

3.RunTime Polymorphism is achieved by ______

friend function
virtual function
operator overloading
function overloading

B. virtual function

4.A function call mechanism that passes arguments to a function by passing a copy of the values of the arguments is __________

call by name
call by value
call by reference
call by value result

B. call by value

5.In C++, dynamic memory allocation is accomplished with the operator ____

new
this
malloc( )
delete

A. new

6.If we create a file by ‘ifstream’, then the default mode of the file is _________

ios :: out
ios :: in
ios :: app
ios :: binary

B. ios :: in

7.A variable defined within a block is visible

from the point of definition onward in the program.
from the point of definition onward in the function.
from the point of definition onward in the block.
throughout the function.

C. from the point of definition onward in the block.

8.The break statement causes an exit

from the innermost loop only.
only from the innermost switch.
from all loops & switches.
from the innermost loop or switch.

D. from the innermost loop or switch.

9.Which of the following cannot be legitimately passed to a function

A constant.
A variable.
A structure.
A header file.

D. A header file.

10.A property which is not true for classes is that they

are removed from memory when not in use.
permit data to be hidden from other classes
bring together all aspects of an entity in one place.
Can closely model objects in the real world.

C. bring together all aspects of an entity in one place.

1.You can read input that consists of multiple lines of text using

the normal cout << combination.
the cin.get( ) function with one argument.
the cin.get( ) function with two arguments.
the cin.get( ) function with three arguments.

C. the cin.get( ) function with two arguments.

2.The keyword friend does not appear in

the class allowing access to another class.
the class desiring access to another class.
the private section of a class.
the public section of a class.

C. the private section of a class.

3.The process of building new classes from existing one is called

Structure
Inheritance
Polymorphism
Template

B. Inheritance

4.If you wanted to sort many large objects or structures, it would be most efficient to

place them in an array & sort the array.
place pointers to them in an array & sort the array.
place them in a linked list and sort the linked list.
place references to them in an array and sort the array

C. place them in a linked list and sort the linked list.

5.Which statement gets affected when i++ is changed to ++i?

i = 20; i++;
for (i = 0; i<20; i++) { }
a = i++;
while (i++ = 20) cout i;

A. i = 20; i++;

6.A friend function to a class, C cannot access

private data members and member functions.
public data members and member functions.
protected data members and member functions.
the data members of the derived class of C.

D. the data members of the derived class of C.

7.The operator that cannot be overloaded is

B. ::

8.A struct is the same as a class except that

there are no member functions.
all members are public.
cannot be used in inheritance hierarchy.
it does have a this pointer.

C. cannot be used in inheritance hierarchy.

9.Pure virtual functions

have to be redefined in the inherited class.
cannot have public access specification.
are mandatory for a virtual class.
None of the above.

A. have to be redefined in the inherited class.

10.Additional information sent when an exception is thrown may be placed in

the throw keyword.
the function that caused the error.
the catch block.
an object of the exception class.

C. the catch block.

1.A virtual class is the same as

an abstract class
a class with a virtual function
a base class
none of the above.

D. none of the above.

2.Identify the operator that is NOT used with pointers

D. >>

3.Consider the following statements char *ptr; ptr = “hello”; cout << *ptr; What will be printed?

first letter
entire string
it is a syntax error
last letter

A. first letter

4.In which case is it mandatory to provide a destructor in a class?

Almost in every class
Class for which two or more than two objects will be created
Class for which copy constructor is defined
Class whose objects will be created dynamically

D. Class whose objects will be created dynamically

5.The members of a class, by default, are

public
protected
private
mandatory to specify

C. private

6.Given a class named Book, which of the following is not a valid constructor?

Book ( ) { }
Book ( Book b) { }
Book ( Book &b) { }
Book (char* author, char* title) { }

B. Book ( Book b) { }

7.Which of the statements is true in a protected derivation of a derived class from a base class?

Private members of the base class become protected members of the derived class
Protected members of the base class become public members of the derived class
Public members of the base class become protected members of the derived class
Protected derivation does not affect private and protected members of the

C. Public members of the base class become protected members of the derived class

8.Which of the following statements is NOT valid about operator overloading?

Only existing operators can be overloaded.
Overloaded operator must have at least one operand of its class type.
The overloaded operators follow the syntax rules of the original operator.
none of the above.

D. none of the above.

9.Exception handling is targeted at

Run-time error
Compile time error
Logical error
All of the above.

A. Run-time error

10.A pointer to the base class can hold address of

only base class object
only derived class object
base class object as well as derived class object
None of the above

C. base class object as well as derived class object

1.Use of virtual functions implies

overloading
overriding
static binding
dynamic binding

D. dynamic binding

2.this pointer

implicitly points to an object
can be explicitly used in a class
can be used to return an object
All of the above

D. All of the above

3.Within a switch statement

Continue can be used but Break cannot be used
Continue cannot be used but Break can be used
Both Continue and Break can be used
Neither Continue nor Break can be used

B. Continue cannot be used but Break can be used

4.Data members which are static

cannot be assigned a value
can only be used in static functions
cannot be defined in a Union
can be accessed outside the class

B. can only be used in static functions

5.Which of the following is false for cin?

It represents standard input.
It is an object of istream class.
It is a class of which stream is an object.
Using cin the data can be read from user’s terminal

C. It is a class of which stream is an object.

6.It is possible to declare as a friend

a member function
a global function
a class
all of the above

D. all of the above

7.In multiple inheritance

the base classes must have only default constructors
cannot have virtual functions
can include virtual classes
None of the above.

C. can include virtual classes

8.Declaration of a pointer reserves memory space

for the object.
for the pointer.
both for the object and the pointer.
none of these.

B. for the pointer.

9.for (; ?

means the test which is done using some expression is always true
is not valid
will loop forever
should be written as for( )

C. will loop forever

10.The operator << when overloaded in a class

must be a member function
must be a non member function
can be both (A) & (B) above
cannot be overloaded

C. can be both (A) & (B) above

1.Function templates can accept

any type of parameters
only one parameter
only parameters of the basic type
only parameters of the derived type

C. only parameters of the basic type

2.How many constructors can a class have?

0
1
2
any number

D. any number

3.The new operator

returns a pointer to the variable
creates a variable called new
obtains memory for a new variable
tells how much memory is available

C. obtains memory for a new variable

4.Consider the following statements: int x = 22,y=15; x = (x>y) ? (x+y) : (x-y); What will be the value of x after executing these statements?

22
37
7
Error. Cannot be executed

B. 37

5.An exception is caused by

a hardware problem
a problem in the operating system
a syntax error
a run-time error

D. a run-time error

6.A template class

is designed to be stored in different containers
works with different data types
generates objects which must be identical
generates classes with different numbers of member functions

B. works with different data types

7.Which of the following is the valid class declaration header for the derived class d with base classes b1 and b2?

class d : public b1, public b2
class d : class b1, class b2
class d : public b1, b2
class d : b1, b2

A. class d : public b1, public b2

8.A library function exit() causes an exit from

the loop in which it occurs
the block in which it occurs
the function in which it occurs
the program in which it occurs

D. the program in which it occurs

9.RunTime polymorphism is achieved by ___________

friend function
virtual function
operator overloading
function overloading

B. virtual function

10.Declaration of a pointer reserves memory space

for the object.
for the pointer.
both for the object and the pointer.
none of these.

B. for the pointer.

1.An array element is accessed using

a FIFO approach
an index number
the operator
a member name

B. an index number

2.A pure virtual function is a virtual function that

has no body
returns nothing
is used in base class
both (A) and (C)

D. both (A) and (C)

3.A static function

should be called when an object is destroyed.
is closely connected with and individual object of a class.
can be called using the class name and function name.
is used when a dummy object must be created.

C. can be called using the class name and function name.

4.We can output text to an object of class ostream using the insertion operator << because

the ostream class is a stream
the insertion operator works with all classes.
we are actually outputting to cout.
the insertion operator is overloaded in ostream

D. the insertion operator is overloaded in ostream

5.The statement f1.write((char*)&obj1, sizeof(obj1));

writes the member function of obj1 to f1.
Writes the data in obj1 to f1.
Writes the member function and the data of obj1 to f1
Writes the address of obj1 to f1.

B. Writes the data in obj1 to f1.

6.To convert from a user defined class to a basic type, you would most likely use.

A built-in conversion function
A one-argument constructor
A conversion function that’s a member of the class.
An overloaded ‘=‘ operator.

C. A conversion function that’s a member of the class.

7.Which of the following is not the characteristic of constructor.

They should be declared in the public section.
They do not have return type.
They can not be inherited.
They can be virtual.

D. They can be virtual.

8.Name the header file to be included for the use of built in function isalnum()

string.h
process.h
ctype.h
dos.h

C. ctype.h

1.A class defined within another class is:

Nested class
Inheritance
Containership
Encapsulation

A. Nested class

2.What will be the values of x, m and n after the execution of the following statements? int x, m, n; m = 10; n = 15; x = ++m + n++;

x=25, m=10, n=15
x=26, m=11, n=16
x=27, m=11, n=16
x=27, m=10, n=15

B. x=26, m=11, n=16

3.Which of the following will produce a value 10 if x = 9.7?

floor(x)
abs(x)
log(x)
ceil(x)

D. ceil(x)

4.The major goal of inheritance in c++ is:

To facilitate the conversion of data types.
To help modular programming.
To extend the capabilities of a class.
To hide the details of base class.

C. To extend the capabilities of a class.

5.Consider the following class definitions: class a { }; class b: protected a { }; What happens when we try to compile this class?

Will not compile because class body of a is not defined.
Will not compile because class body of b is not defined
Will not compile because class a is not public inherited
Will compile successfully.

D. Will compile successfully.

6.Which of the following expressions is illegal?

(10 6).
(false && true)
bool (x) = (bool)10;
float y = 12.67;

C. bool (x) = (bool)10;

7.The actual source code for implementing a template function is created when

The declaration of function appears.
The function is invoked.
The definition of the function appears.
None of the above.

B. The function is invoked.

8.An exception is caused by

a runtime error.
a syntax error.
a problem in the operating system.
a hardware problem.

A. a runtime error.

9.Which of the following statements are true in c++?

Classes can not have data as public members.
Structures can not have functions as members.
Class members are public by default.
None of these.

B. Structures can not have functions as members.

10.What would be the output of the following program? int main() { int x,y=10,z=10; x = (y = =z); cout<<

1
0
10
Error

A. 1

1.What is the error in the following code? class t { virtual void print(); }

No error.
Function print() should be declared as static.
Function print() should be defined.
Class t should contain data members.

A. No error.

2.What will be the output of following program? #include void main() { float x; x=(float)9/2; cout x; }

A. 4.5

3.A white space is :

blank space
new line
tab
all of the above

D. all of the above

4.The following can be declared as friend in a class

an object
a class
a public data member
a private data member

B. a class

5.What would be the output of the following? #include void main() { char *ptr=“abcd” char ch; ch = ++*ptr++; cout ch; }

B. b

6.A copy constructor takes

no argument
one argument
two arguments
arbitrary no. of arguments

B. one argument

7.Overloading a postfix increment operator by means of a member function takes

no argument
one argument
two arguments
three arguments

A. no argument

8.Which of the following ways are legal to access a class data member using this pointer?

this.x
*this.x
*(this.x)
(*this).x

D. (*this).x

9.If we store the address of a derived class object into a variable whose type is a pointer to the base class, then the object, when accessed using this pointer.

continues to act like a derived class object.
Continues to act like a derived class object if virtual functions are called.
Acts like a base class object.
Acts like a base class, if virtual functions are called.

B. Continues to act like a derived class object if virtual functions are called.

10.Which of the following declarations are illegal?

void *ptr;
char *str = “hello”;
char str = “hello”;
const *int p1;

C. char str = “hello”;

1.What will be the result of the expression 13 & 25?

C. 9

2.Which of the following operator can be overloaded through friend function?

D. *

3.To access the public function fbase() in the base class, a statement in a derived class function fder() uses the statement.fbase();

fbase();
fder();
base::fbase();
der::fder();

A. fbase();

4.If a base class destructor is not virtual, then

It can not have a function body.
It can not be called.
It can not be called when accessed from pointer.
Destructor in derived class can not be called when accessed through a pointer to the base class.

D. Destructor in derived class can not be called when accessed through a pointer to the base class.

5.Maximum number of template arguments in a function template is

one
two
three
many

D. many

6.In access control in a protected derivation, visibility modes will change as follows:

private, public and protected become protected
only public becomes protected.
public and protected become protected.
only private becomes protected.

C. public and protected become protected.

7.Which of the following statement is valid?

We can create new C++ operators.
We can change the precedence of the C++ operators.
We can change the associativity of the C++ operators.
We can not change operator templates.

D. We can not change operator templates.

8.What will be the output of the following program? #include iostream.h void main() { float x=5,y=2; int result; result=x % y; cout result; }

1
1.0
Error message
2.5

C. Error message

9.Which can be passed as an argument to a function?

constant
expression
another function
all of the above.

A. constant

10.Member functions, when defined within the class specification:

are always inline.
are not inline.
are inline by default, unless they are too big or too complicated.
are not inline by default.

A. are always inline.

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