Specimen Question Paper Computer Scie ne ISC : Plus Two / 12th Std / +2

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Document Described : Computer Sciene Question Paper, ISC Question Paper

COMPUTER SCIECE
PAPER 1
(THEORY)
Three hours
(Candidates are allowed additional 15 minutes for only reading the paper.
They must NOT start writing during this time.)
Answer all questions in Part I (compulsory) and seven questions from Part-II, choosing three 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 [ ].

http://www.cisce.org/isc_XII_SpecimanQP_2012-13.html
http://www.cisce.org/ISC%202013%20Sp...%20Science.pdf

PART I
Answer all questions.
While answering questions in this Part, indicate briefly your working and reasoning, wherever required.
Question 1
(a) State the two distributive laws of Boolean Algebra. Prove any one of them with the help of Truth Table. [2]

Question 2
(a) What do LIFO and FIFO stand for? [2]
(b) For an array of real numbers x [ - 6… 8 , -12… 20 ] , find the address of x [5] [4 ], if x [1] [1] is stored in location 100 in the column major order. Assume that each element requires 4 bytes. [2]
(c) State the difference between an abstract class and an interface [2]
(e) Define a binary tree. [2]

Question 3
(a) The following function is a part of some class. It returns the value 1 when the number is an Armstrong number, otherwise it returns 0.
/* An Armstrong number is a number which is equal to the sum of the cube of its individual digits */
int arms ( int n )
{
int digit = 0, sum = 0 ;
int rem = n;
while ( ? 1 ? )
{
digit = ? 2 ?;
sum = sum + ? 3 ? ;
rem = ? 4 ? ;
}
if (? 5 ? )
return 1 ;
else
return 0 ;
}
(i) What is the expression/value at ? 1 ? [1]
(ii) What is the expression/value at ? 2 ? [1]
(iii) What is the expression/value at ? 3 ? [1]
(iv) What is the expression/value at ? 4 ? [1]
(v) What is the expression/value at ? 5 ? [1]

(b) 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]

PART – II
Answer seven questions in this part, choosing three questions from
Section A, two from Section B and two from Section C.
SECTION - A
Answer any three questions.
Question 4
(a) Given the Boolean function:
F ( P, Q, R, S ) = N( 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. [5]
(b) Given the Boolean function :
X ( P, Q, R, S ) = N( 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. [5]

Question 5
The main safe in the nationalized bank can be opened by means of a unique password consisting of three parts. Different parts of the password are held by the Chairman, Regional Manager, Bank Manager and Head cashier of the bank, respectively. In order to open the safe, any one of the following conditions must be satisfied:
The password of the Chairman, together with passwords of any two other officials, must be entered.
OR
The password of all the three bank officials, excluding the chairman, must be entered.
The inputs are:
A : Denotes the Chairman’s password.
B : Denotes the Regional Manager’s password.
C : Denotes the Bank Manager’s password.
D : Denotes the Head Casher’s password.
Output:
X – Denotes that the safe can be opened.
[1 indicates Yes and 0 indicates No in all cases]
(a) Draw the truth table for the inputs and outputs given above and write the SOP expression for X( A, B, C, D ). [5]
(b) Reduce X( A, B, C, D ) using Karnaugh’s map, if possible.
Draw the logic gate diagram for the reduced SOP expression for X( A, B, C, D ) using AND & OR gates. You may use gates with two or more inputs. Assume that the variables and their complements are available as inputs.
[5]

Question 7
(a) Define Cardinal Form of an expression and Canonical Form of an expression. Give an example for each. [3]
(b) Which gate is equivalent to :
(NOR) OR (XOR) [3]
(c) Define a Half Adder. Draw the Truth Table and Logic diagram of a Half Adder. [4]

SECTIO – 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 8
A perfect square is an integer which is the square of another integer. For example, 4, 9,
16 .. are perfect squares. Design a Class Perfect with the following description: [10]
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 9
A class RecFact defines a recursive function to find the factorial of a number. The details of the class are given below: [10]
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 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.