CBSE Board Class 12 Computer Science Sample Papers 2011

Sample Paper – 2011
Class – XII
Subject - Computer Science

Time allowed : 3 hours                                Maximum marks : 70


Note :
i)All the questions are compulsory .
ii)Programming Language  : C++ .


1.a) What is the difference between Auto variables and Static variables? Give an example
     to illustrate the same.              2                 

b) Name the header files for the following functions           2
(1)cgets
(2)floor
(3)isalpha
(4)  gets 

c)In the following C++ program what is expected value of myscore from options  (i) to (iv)      
     given  below.          2
              #include<stdlib.h>
             #include<iostream.h>
void main(  )
{
   randomize( );
             int score[]={ 25, 20,34,56, 72, 63};
             int myscore=score[2+random(2)];
            cout<<myscore<<endl;
            }
     i) 25  ii) 34  iii) 20  iv) None of these                                              

d)Give the output of thefollowing program (Assuming all required header files are included
          in the program ).          2
void swap(char &c1,char &c2)
{ char temp;
temp=c1;
c1=c2;
c2=temp;
  }
     void update(char *str)
     {         int k,j,l1,l2;
    l1 = (strlen(str)+1)/2;
    l2=strlen(str);
     for(k=0,j=l1-1;k<j;k++,j--)
     {
  if(islower(str[k]))
   swap(str[k],str[j]);
        }
    for(k=l1,j=l2-1;k<j;k++,j--)
    {
      if(isupper(str[k]))
   swap(str[k],str[j]);
               }
        }


void main()
{  
   char data[100]={"gOoDLUck"};
cout<<"Original Data : "<<data<<endl;
update(data);
cout<<"Updated Data "<<data;
}

  e)  Give the output of the following program segment :                                                  3
       void main()
     {  int x[] = { 11,22, 33, 55, 112};
          int *p = x ;
           while(*p<110)
          {  if(*p%3 !=0)
                *p=*p+1 ;
              else
                  *p=*p+2 ;
               P++ ;
           }          
           for( int i=4 ;i>=1 ;i--)
         {   cout<<x[i]<< ‘*’ ;
           if(i%3= =0 )
          cout<<endl ;
        } cout<<x[0]*3<<endl ;
      }       


Q-2 a. Define Multilevel and Multiple Inheritance with example .                                  2
    
       b. Define a class ELECTION in C++ with the following descriptions:                    4 
           Write a suitable main ( ) function also to declare 3 objects of ELECTION type and
            find the winner and display the details .
Private members :
Data :  candidate_name , party , vote_received
Public members :
Functions  : Enterdetails ( ) – To input data
    Display ( ) –         To display the details of the winner
    Winner ( ) –          To return the details of the winner trough the object after 
                                                                             comparing the  votes received by three candidates .

d.Answer the questions (i) to (iv) based on the following code :
        class RED                   4
{
  char n [ 20 ];
  void input ( );
protected :
  int x , y ;
  void read ( );
public :
  RED ( );
  RED ( int a );
  void get_red ( );
  void put_red ( );
};
class WHITE : protected RED
{
  void a , b ;
protected :
  int c , d ;
  void get_white( );
public:
  WHITE ( );
  Void put_white ( );
};
class BLACK : private WHITE
{
  void * p ;
  char st[20];
protected :
  int q;
  void get_black( );
public:
  BLACK ( );
  void put_black ( );
}ob;

a.Name the data members and functions which are accessible by the objects of class BLACK.
b.Give the size of object ob
c.Name the OOPS concept implemented above and its type .
d.Name the members accessible by function get_black( );



3.a) Write a function in C++ to delete a name from a list of names.                         3         
              
   b) An array A[13][14] is  stored  in  the  memory  along  the column with each element
        occupying 4 bytes. Find out the Base address and address of the element A[3][7]
         if the element A[4][4] is stored at the address 1300.                                                      4 


c) Consider the following portion of a program , which implements names queue for  Books .
     Write the definition of function Insert(), to insert a new node in the queue with required
      information  .                                                           4
struct Book
{
char names[4][20];
};
class QueueofBooks
{
Book Q[10];
public :
int front ,rear;
QueueofBooks()
{
  front=rear=-1;
}
void Insert();
void Delete();
};

d) Write a function in C++ which accepts a 2D array of integers and its size as arguments      and displays elements which are exactly two digit number.                                                  3
              If 2D array is 
             Output is
             14 25 32 45 11 28 18 
 
e) Evaluate the following postfix expression using a stack and show the contents of stack
    after execution of each operation:  A-B+C*D^E*G/H                                                   3



5.a) Observe the program segment given below carefully and answer the question that follows :                1 
  class college
{ private :
            char name[25];
             int numstu;
     public:
  void incollege( );
  void outcollege( );
  int retnumstu( )
  { return numstu; }
};
void modify(college A)
{ fstream INOUT;
  INOUT.open(“college.dat”,ios::binary|ios::in|ios::ate);
  college B;



  int recread=0, found=0;
  while(!found && INOUT.read((char*)&B,sizeof(B))
{ recread++;
  if(A.retnumstu( )= = B.retnumstu( ))
  {
                              ____________________________// statement1
   INOUT.write((char*)&A,sizeof(A));
   Found=1;
    }
   else
    INOUT.write((char*)&B,sizeof(B));
   }
  if(!found)
   cout<<”\nRecord for modification does not exist”;
  ________________  ;  // statement2  }

If the function modify( ) is supposed to modify a record in file college.dat with the values of college A passed to its argument, write the appropriate statement for missing statement1 using seekp( ) or  seekg( ), whichever needed, in the above code that would write the modified record at its  proper place and fill also for statement 2 .

 b)Write a function in C++ to transfer a particular type of stock from the file “stock.dat”  to another   file “Site.dat”. Assuming that the binary file is  containing the records of following structure:          2        
struct Products
{
  int id;
  char Iname[30];
  int type;
};
           Remember that transfer means deletion from the “stock.dat” file and addition in the “site.dat” file.

  c) Assume that a text file named “MATHS.TXT” contains text and some mathematical operators written into  it.      “MATHS.TXT”  contains  only  five  types  of  operator   ‘+’ , ‘−’ , ‘*’ , ‘/’ , ‘=’.Write a function named copyoperator() that reads   the file “MATHS.TXT” and create a new filenamed “OPERATOR.TXT”, to contain only operators from the file “MATHS.TXT”.
      In “OPERATOR.TXT” operators are separated by comma.                           3
            For example: If “MATHS.TXT” contains
                                        Result of 2 + 4 * 3 = 14
    Result of 16 / 2 + 1 = 9
              Then the file “OPERATOR.TXT” shall contain
                                         + , * , = , / , +
6.(a)What do you understand by Primary Key. Give one database example .                    2

       (b). Write the SQL statement for the following :
       (i)    Display all distinct records from PREPAID .
      (ii)   To display the Model & Amount for Preeti , Suchismita & Pavani .
      (iii)  Create a view called  ITSECTOR , which contains all the information of PREPAID

     table whose  Connection is Hutch or Model is Nokia .  
     (iv)  Find all customer name whose model is same as of  Suchismita .
     (v)  select Cname , Cmodel , Amount form PREPAID , POSTPAID where PREPAID.Vrno = POSTPAID.Vno ; 
     (vi)    select  Connection , sum(Amount) from PREPAID group by Connection ;
    (vii)    select * from  PREPAID where Model is NULL ;  .
    (viii)   select Model , count(*) from PREPAID  group by Model Having Amount >800 ;

7  (a) State and prove the Distributive law algebraically.   2

       b) Write the equivalent POS expression of following  SOP form
           F (x,y,z)= ∑ (0,2,4,6)        2

       c)  Draw the Logical circuit of the following expression with the help of NOR gate only                 
            x+yz .            1

        d) Obtain the simplified form of a Boolean expression using K-Map.                                             
             F(a,b,c,d)=∑(0,1,2,3,4,7,11,12,14)       3

8.  (a) What  are cookies.   1

      (b) Define the term Bandwidth. Give unit of  Bandwidth.    1

      (c)  Expand the following terminology : (i) NSF  (ii) ARPANET    1

      (d) Define the term NIU.    1
     
      (e)  Distinguish between star and Bus topology    2