Class 12 Computer Science Previous Year Question Paper 2020

This page contains class 12 computer science previous year question paper 2020 for ASSEB (formerly AHSEC) students.

Students can use this question paper for exam preparation, practice and revision. Solving previous year question papers can help students understand the question pattern and important topics.

(Theory)

Full Marks : 70

Pass Marks : 21

Time: 3 hours

I.Answer the following (any 8)                                                    1x8=8

a) What is a constructor?

b) What is inheritance?

c) What is the purpose of ‘new’ operator in C++?

d) Give an example of non-linear data structure.

e) When do we use ALTER TABLE command in SQL.

f) What is a logic gate?

g) Write the full form of SMTP.

h) Give an example of web browser

2)Answer the following questions (any 10)                                            2x10=20

a) Differentiate between Abstract class and concrete class.

b) What is meant by member variables and member functions?

c) Distinguish between Ofstream and Ifstream classes.

d) Suppose an array ‘arr’ contains 3 elements. How would you declare and initialize a pointer to this array?

e) Describe the 2 operations that can be performed on a stack.

f) What is the difference between CHAR and VARCHAR2 data type in SQL?

g) Describe the use of GROUP BY clause in SQL with an example.

h) State DeMorgan’s law in Boolean Algebra.

i) What are the limitations of Karnaugh Map.

j) Differentiate between Router and Switch

3)Answer the following                                                                                              3x9=27

a)Explain how polymorphism can be implemented using function overloading.

b) Describe the mechanism of accessing data members and member functions in the following cases:

  1. Inside the main program
  2. Inside a member function of the same class
  3. Inside a member function of another class

c) Rewrite the following program after removing the syntax errors (3)

#include<iostream.h>

class Room

{

int length;

int width;

public

Room()

{           length=0;

             width=0;

}

Room (int value=8)

{

length=width=8;

}

void display( )

{

cout<<length<<’’ <<width;

}

};

void main( )

{

Room obj Room1;

obj Room1.display( );

}

                                  OR

Write a program in C++ to demonstrate constructor overloading.

 

d)Convert the following infix expression into postfix

 (A*B – (C – D))/(E + F)

                                  OR

Calculate the value of the following postfix expression

 54 6 + 7 4 – * 9/35  15 + +

 

e) Write the steps to search 23 using binary search in the following array

A

258121623385672

                                            OR

Write the algorithm for Selection sort.

 

f) Differentiate between ‘IN’ and ‘BETWEEN’ operator in SQL with example.

                                             OR

Write the necessary SQL commands to create a table STUDENT with the following attributes

Roll_No           integer

Name              char (35)

address           varchar2 (70)

Set the Roll_No as the primary key of the table.

 

g) Identify each of the following logic gates by name and construct their respective truth table.

                                          OR

Construct a truth table for the following function and from the truth table obtain an expression for the inversion function

F (A, B, C) = A + BC’

h)Write the advantages of STAR topology.

i)Write a short note on twisted pair cable.

                                    OR

Write a short note on Firewall

4)Explain different types of inheritance available in C++.                                           [5]

                                    OR

Explain the visibility modes available in c++ with example.

5)Describe the basic functions available in C++ for file operations.                            [5]

                                    OR

Write a C++ program to create a new file and write some lines to it.

6)Write a C++ program to implement a Stack.                                                    [5]                                     

                                       OR

Write a C++ program to implement a Queue.

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