Saturday, February 18, 2017

ISC computer Science class XII sample paper 7

ISC computer science class XII sample paper 7


Answer all questions in Part I (compulsory) and seven questions from Part-II, choosing two 
questions from Section-A, two from Section-B and two from Section-C.
All working, including rough work, should be done on the same sheet as the rest of the answer.


The intended marks for questions or parts of questions are given in brackets [ ].
___________________________________________________________________

                                                                                                     PART I

Answer all questions.

While answering questions in this Part, indicate briefly your working and reasoning, wherever required.

Question 1                                                                                                          [1X5=5]


(a)
State the two distributive laws of Boolean Algebra.  Prove any one of them with



the help of Truth Table.


(b)
Draw the truth table to verify the expression :



p q is equivalent to q ⇒ ∼ p






( q = q = q’)


(c)
Find the complement of the following:



[(xy)′ • x] [ (xy)′ • y]


(d)
Simplify the following Boolean Expression using laws of Boolean Algebra.  At



each step, clearly state the law used for simplification.



z . ( z + x ). x . ( y +  y )


(e)
Given



F ( x, y, z ) = xz + xy + yz



Write the function in canonical sum of products form.











1







Question 2                                                                                                                             

(a)      What do LIFO and FIFO stand for?                                                                      [2]

(b)                For an array of real numbers x [6][20], find the address of x [5] [4 ], if x [0] [0] is stored in location 100 in the column major order. Assume that each element requires 4 bytes.                                                                                                [2]

(c)
State the 2 difference between an constructor and function
[2]
(d)
Convert the following infix expression to its postfix form:
[2]

b * [ (a / d ) -  ( c * ( e - f ) ) ]

(e)
Define a binary tree.
[2]


Question 3


Give output of the following function where x and y are arguments greater than 0. Show the dry run/working.

int strange (int x, int y)
{
//Assuming x>0 and y>0
if(x>=y)
{
x = x-y;
return strange(x , y);
}
else
return x;
}

(i)     What will the function strange(20,5) return ?                                             [2]

(ii)    What will the function strange(15,6) return ?                                             [2]

(iii)   In one line, state what the function is doing.                                               [1]



PARTII

Answer seven questions in this part, choosing two questions from
Section A, two from Section B and two from Section C.

SECTION- A
Answer any three questions.


Question 4

(a)      Given the Boolean function:                                                                                 [5]
F ( P, Q, R, S ) =   ( 0, 1, 3, 4, 5, 6, 7, 9, 10, 11, 13, 15 )

Use Karnaugh’s map to reduce the function F, using the SOP form. Draw a logic gate diagram for the reduced SOP form. You may use gates with more than two inputs. Assume that the variable and their complements are available as inputs.

(b)      Given the Boolean function :                                                                                [5]

X ( P, Q, R, S ) =  Ï€ ( 3, 8, 10, 12, 13, 14, 15 )

Use Karnaugh’s map to reduce this function X using the given POS form. Draw
a logic gate diagram for the reduced POS form.  You may use gates with more

than two inputs.  Assume that the variables and their complements are available
as inputs.

Question 5

 (a)
Draw the truth table and logic circuit diagram for a Decimal to Binary Encoder.
[5]
(b)
Given :
F(x, y, z) =   (1,3,7)
[2]

Verify :
F(x, y, z) = Ï€  (0,2,4,5,6) if both are equal

(c)
Simplify the following expression by using Boolean laws. Show the working and
[3]

also mention the laws used :


X’Y’Z’ + XYZ’ + XY’Z’ + X’YZ’


Question 6


(a)
Define SOP Form of an expression and POS Form of
an expression.
[3]

Give an example for each.


(b)
Which gate is equivalent to :

[3]

(NOR) OR (XOR)


(c)
Define a Half Adder. Draw the Truth Table and Logic diagram of a Half Adder.
[4]

SECTION B



Answer any two questions.



Each program should be written in such a way that it clearly depicts the logic of the problem.

This can be achieved by using mnemonic names and comments in the program.

(Flowcharts and Algorithms are not required.)

The programs must be written in Java.
Question 7


A perfect square is an integer which is the square of another integer.  For example, 4, 9,
[10]
16 .. are perfect squares. Design a Class Perfect with the following description:

Class name

:
Perfect





Data members/instance variables







n

:
stores an integer number

Member functions:







Perfect( )
:
default constructor



Perfect(int)
:    parameterized constructor to assign a




value to ‘n’




void perfect_sq()
:    to display the first 5 perfect squares




larger than ‘n’ (if
n = 15, the next 3




perfect squares are 16, 25, 36)

void sum_of()
:
to   display   all   combinations   of




consecutive  integers  whose  sum  is




equal to n. ( the number n = 15 can be




expressed as







1
2
3
4
5




4
5
6






7
8




Specify  the  class  Perfect  giving details of the constructors, void perfect_sq( ) and

void sum_of().
Also define the main function to create an object and call methods

accordingly to enable the task.









Question 8





A class RecFact defines a recursive function to find the factorial of a number.
The
[10]
details of the class are given below:




Class name

:
RecFact


Data members/instance variables




n

:
stores the number whose factorial





is required.


r

:
stores an integer


Member functions





RecFact( )

:
default constructor


void readnum( )

:    to enter values for ‘n’ and ‘r’


int factorial(int)

:    returns the factorial of the number
using




the Recursive Technique.


Void factseries(
)
:    to calculate and display the value of





n!+(r-2)!





    ( n r)!



Specify the class RecFact giving the details of the constructor and member functions void readnum( ), int factorial(int) and void factseries( ). Also define the main function to create an object and call methods accordingly to enable the task.


Question 9


In “Piglatin” a word such as
KING is replaced by INGKAY , while TROUBLE
[10]
becomes OUBLETRAY and so on . The first vowel of the original word becomes

the start of the translation, any
preceding letters being shifted towards the end and

followed by AY.



Words that begin with a vowel or which do not contain any vowel are left unchanged.

Design a class Piglatin using the description of the data members and member functions given below:

Class name

:
Piglatin
Data members /instance variables :



Txt
:
to store a word
len
:
to store the length














Member functions :



Piglatin( )
:  constructor to initialize the data mrmbers

void readstring( )
:
to accept the word input in UPPER CASE
void convert ( )
:
converts  the word into its piglatin form
and


displays the word (changed or unchanged)
void consonant( )
:
counts and displays the number of







Consonents present in the given word.



Specify the class Piglatin giving the details of the constructor, void readstring( ), void convert( ) and void consonant( ). Also define the main function to create an object and call methods accordingly to enable the task.

SECTION C

Answer any two questions.

Each program should be written in such a way that it clearly depicts the logic of the problem stepwise.

This can be achieved by using comments in the program and mnemonic names or pseudo codes for algorithms. The programs must be written in Java and the algorithms must be written in general / standard form, wherever required / specified.


(Flowcharts are not required.)

Question 10



A class Author contains details of the author and another class Book List contains
[5]
details of the books written by him. The details of the two classes are given below:

Class name
:
Author

Data members



authorno
:
stores the author’s number

name
:
stores the author’s name

Member functions



Author ( )
:
default constructor

Author ( … )
:
parameterised constructor to assign values



to author number and name

void show( )
:
to display the author’s details








7



Class name
:
Booklist
Data members/instance variables


bookno
:
Long type variable to the store book number
bookname
:
stores the book name
price
:
float variable to store the price
edition
:
integer type variable to store the edition


number
Member functions


Booklist (…)
:
parameterized constructor to assign values to


data members of both the classes
void show( )
:
to display all the details

Specify the class Author giving details of the constructors and member function void show( ). Using the concept of Inheritance, specify the class Booklist giving details of the constructor and the member function void show( ). Also define the main function to create an object and call methods accordingly to enable the task.

Question 11




In a computer game, a vertical column and a pile of rings are displayed.  The objective
[5]
of the game is to pile up rings on the column till it is full.  It can hold 10 rings at the


most.  Once the column is full, the rings have to be removed from the top till the column


is empty and then the game is over.

Define the class RingGame with the following


details:




Class name
:
RingGame


Data members/instance variables




ring [ ]
:
array to hold rings (integer)


max
:    integer to hold maximum capacity of ring array
upper
:
integer to point to the upper most element


Member functions




RingGame(int m)
:    constructor to initialize, max = m & upper to –


1.


void jump-in(int )
:    adds  a  ring  to  the  top  of  the  column,
if


possible.   otherwise,   displays   a   message


“Column full. Start removing rings”.









8







void jump-out( )
:    removes the ring from the top, if column is not

empty.
otherwise,
outputs
a
message,

“Congratulations. The game is Over”.


Specify the class RingGame giving the details of the constructor and functions void jump-in(int) and void jump-out( ). Also define the main function to create an object and call methods accordingly to enable the task.


Question 12

(a)     A Linked List is formed from the objects of the class,                                                      [2]

Class Node

{

int num;

Node next;

}

Write the algorithm OR a method for inserting a node in the end of the list.

The method declaration is given below :

void insertnode(₃ode start)


(c)     List the nodes in the tree given below using:                                                               [3]

(i)            Preorder Traversal

(ii)          Postorder Traversal

(iii)        Inorder traversal

F



H

G

                             J                         P                                 M
                            I
                                                                                       
K                     L                                                            O                          N


9



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