C++ Mock Test


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This section presents you various set of Mock Tests related to C++ Framework. You can download these sample mock tests at your local machine and solve offline at your convenience. Every mock test is supplied with a mock test key to let you verify the final score and grade yourself.

Questions and Answers

C++ Mock Test I

Q 1 - The default access specifer for the class members is

A - public

B - private

C - protected

D - None of the above.

Answer : B

Explaination

If a member/s appear in the class with following no access specifier, the default is private.

Q 2 - A trigraph character begins with

A - #

B - ##

C - ?

D - ??

Answer : C

Explaination

Few characters have alternative representation and start with ??. Eg. Fro [ equivalent is ??(

Answer : D

Explaination

C++ supports all the forms of inheritance.

Answer : A

Explaination

As inline function gets expanded at the line of call like a macro it executes faster.

Q 5 - Choose the pure virtual function definition from the following.

A - virtual void f()=0 { }

B - void virtual f()=0 { }

C - virtual void f() {} = 0;

D - None of the above.

Answer : D

Explaination

A pure virtual function cannot have a definition.

Answer : B

Explaination

It is sufficient to have one pure virtual function in the class to make it as an abstract class.

Q 7 - What is the output of the following program?

#include<iostream>

using namespace std;
class abc { 
   void f();
   void g();
   int x;
};

main() {
   cout<<sizeof(abc)<<endl;
}

A - 12

B - 4

C - 8

D - Compile error

Answer : B

Explaination

Only the class member variables constitutes as the size of the class or its object.

#include<iostream>

using namespace std;
class abc { 
   void f();
   void g();
   int x;
};
main() {
   cout<<sizeof(abc)<<endl;
}

Q 8 - What is the output of the following program?

#include<iostream>

using namespace std;
class abc { 
   public: 
      static int x; 
      int i; 

      abc() {
         i = ++x;
      }
   };
int abc::x;

main() { 
   abc m, n, p;
   
   cout<<m.x<<" "<<m.i<<endl;
}

A - 3 1

B - 3 3

C - 1 1

D - 1 3

Answer : A

Explaination

The static member variable ‘x’ shares common memory among all the objects created for the class.

#include<iostream>

using namespace std;
class abc { 
   public: 
      static int x; 
      int i; 

      abc() {
         i = ++x;
      }
   };
int abc::x;

main() { 
   abc m, n, p;
   
   cout<<m.x<<" "<<m.i<<endl;
}

Q 9 - A constructor can be virtual.

A - True

B - False

Answer : B

Explaination

The purpose of the constructor cannot be overridden in the derived class hence constructor cannot be a virtual.

Q 10 - Choose the operator which cannot be overloaded.

A - /

B - ()

C - ::

D - %

Answer : C

Explaination

Scope resolution (::) is not permitted to be overloaded.

Q 11 - Which operator is required to be overloaded as member function only?

A - _

B - _ _

C - ++ (postfix version)

D - =

Answer : D

Explaination

Overloaded assignment operator does the job similar to copy constructor and is required to be overloaded as member function of the class.

Q 12 - Which of the following is not the keyword in C++?

A - volatile

B - friend

C - extends

D - this

Answer : C

Explaination

All the rest are valid keywords of C++.

Q 13 - What is the output of the following program?

#include<iostream>

using namespace std;
class abc { 

   public: 
      int i; 

      abc(int i) { 
         i = i;
      }
};

main() { 
   abc m(5); 
   
   cout<<m.i;
}

A - 5

B - Garbage

C - Error at the statement i=i;

D - Compile error: ‘i’ declared twice.

Answer : B

Explaination

i=i, is assigning member variable to itself.

#include<iostream>

using namespace std;
class abc { 

   public: 
      int i; 

      abc(int i) { 
         i = i;
      }
};

main() { 
   abc m(5); 
   
   cout<<m.i;
}

Answer : C

Explaination

If no access specifiers are specified for structure variables/functions, then the default is considered as public.

Q 15 - From the below class choose the proper definition of the member function f().

template <class T>

class abc {
   void f();
};

A - template <class T>

    void abc<T>::f() { }

B - template<class T>

    void abc::f() { }

C - template<T>

    void abc<class T>::f() { }

D - template<T>

    void abc<T>::f() { }

Answer : A

Explaination

Q 16 - Choose the respective delete operator usage for the expression ‘ptr=new int[100]’.

A - delete ptr;

B - delete ptr[];

C - delete[] ptr;

D - []delete ptr;

Answer : C

Explaination

Q 17 - ‘cin’ is an __

A - Class

B - Object

C - Package

D - Namespace

Answer : B

Explaination

It’s an object of istream class.

Q 18 - The operator used to access member function of a structure using its object.

A - .

B - ->

C - *

D - None of the above.

Answer : A

Explaination

Just the way we use dot (.) operator to access members of the class, in similar it is used to access the members of the structure too.

Q 19 - A user defined header file is included by following statement in general.

A - #include “file.h”

B - #include <file.h>

C - #include <file>

D - #include file.h

Answer : A

Explaination

With the syntax as in (a) the compiler first looks for the file in the present working directory and then in the default include path if not found.

Q 20 - Which data type can be used to hold a wide character in C++?

A - unsigned char;

B - int

C - wchar_t

D - none of the above.

Answer : C

Explaination

wchar_t is the data type using which we can hold Unicode characters.

Q 21 - Which is the storage specifier used to modify the member variable even though the class object is a constant object?

A - auto

B - register

C - static

D - mutable

Answer : D

Explaination

mutable is storage specifier introduced in C++ which is not available in C. A class member declared with mutable is modifiable though the object is constant.

Q 22 - The following operator can be used to calculate the value of one number raised to another.

A - ^

B - **

C - ^^

D -None of the above

Answer : D

Explaination

There is no such operator in C/C++.

Q 23 - Pick up the valid declaration for overloading ++ in postfix form where T is the class name.

A - T operator++();

B - T operator++(int);

C - T& operator++();

D - T& operator++(int);

Answer : B

Explaination

The parameter int is just to signify that it is the postfix form overloaded. Shouldn’t return reference as per its original behavior.

Q 24 - We can have varying number of arguments for the overloaded form of () operator.

A - True

B - False

Answer : A

Explaination

Answer : B

Explaination

Both the mentioned operators cannot be overloaded.

Answer Sheet

Question Number Answer Key
1 B
2 C
3 D
4 A
5 D
6 B
7 B
8 A
9 B
10 C
11 D
12 C
13 B
14 C
15 A
16 C
17 B
18 A
19 A
20 C
21 D
22 D
23 B
24 A
25 B

cpp_questions_answers.htm

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