Computer Science : CBSE Class XII Important Questions Computer Science (2008)

Q. 1. Distinguish between an object and a class.

Ans: An object is an identifiable entity with some characteristics and behaviour. A class is a group of objects that share common properties and relationships.

Q. 2. What is polymorphism? Give an example in C++ to show its implementation in C++.

Ans: Polymorphism is the property by which the same message can be processed in more than one form. This is of 2 types:

1. Function Overloading: Same function name can be used for more than one purpose.

2. Operator Overloading: Same operator can be used for more than one purpose

Q. 3. How does a pointer variable differ from a simple variable?

Ans: A simple variable stores a data value whereas a pointer variable stores a memory address of another variable.

Q. 4. Name the header file to be included for the use of following built-in functions:

1. frexp( )

2. tooupper( )

3. getc( )

4. strcat( )

5. setw( )
   

Ans:

1. math.h

2. ctype.h

3. stdio.h

4. string.h

5. iomanip.h

Q. 5. Find the syntax errors:

# include(iostream.h)
void main( )
{
      int X, Y;
      cin>>X;
      for(Y=0;Y<10,Y++)
                  if X = = Y
                              cout<<Y+X;
                  else
                              cout<<Y:
}

Errors:

File iostream.h should be in angled brackets < > i.e. #include<iostream.h>

The condition and updation segments should be separated by a semicolon(;) i.e. For(Y=0;Y<10;Y++)

The condition should be enclosed in braces as shown below: i.e. if(X= = Y)

Statement should be terminated by ; i.e. cout<<Y;

Q. 6. Will the following program execute successfully? If not, state the reason(s):

# include<isotream.h>
void main( )
{
            int x, sum = 0;
            cin<<n;
            for(x=1,x<100,x+=2)
                        if x%2 = = 0
                                    sum += x;
                        cout>>”SUM=”>>SUM;
}

 

            Ans: #include<iostream.h>       
                    Wrong operator with cin. It should be cin>>n;
                    In place of if x%2 = = 0, it should be if(x%2 = = 0)
                    Wrong operator with cout. It should be cout<<”SUM=”<<SUM;

 

Q. 7. What will be the output:

int fun(int &x, int y=10)
{
            if(x%y = = 0) return ++x; else return y--;
}
void main( )
{
            int p=20, q=23;
            q = fun(p,q);
            cout<<p<<” “<<q<<endl;
            p = fun(q);
            cout<<p<<” “<<q<<endl;
            q = fun(p);
            cout<<p<<” “<<q<<endl;
}

Ans: Output is:
            20 23
            10 23
            11 11

Q. 8. Write a function in C++ to find the sum of the following series:

1+2+3+4+5+6+7+………. upto n terms.

Ans:

#include<iostream.h>
#include<conio.h>
int sum_series(int n);
void main( )
{
            clrscr( );
            int t = 0, sum = 0;
            cout<<”How many terms?”;
            cin>>t;
            sum = sum_series(t);
            cout<<”\n The sum of the series 1+2+3+4+....upto”<<t<<”is”<<sum;
}
int sum_series(int n)
{
            int s = 0;
            for(int i =1;i<=n;i++)
                        s+=i;
            return s;
}

 

Q. 9. Write a C++ function SUMFUN( ) having two parameters X of type double and n of type integer with a result type as double to find the sum of the series given below:

X + X2/3!+ X3/5!+…….+ Xn/(2n-1)!
            Ans:
                        double SUMFUN(double X, int N)
                        {
                                    int i,j;
                                    double sum = 0; fact;
                                    for(i=1;i<=n;++i)
                                    {
                                                fact = 1;
                                                for(j=1;j<=2*i-1;++j)
                                                            fact = fact * j;
                                                sum = sum + pow(x,i)/fact;
                                    }
                                    return sum;
                        }

Chapter 2 – Structures

Q. 10. Find the output of the following programs:

# include<iostream.h>

struct point
{
      int X,Y;
};
void show(point p)
{
      cout<<p.x<<’:’<<p.y<<endl;
}
void main( )
{
      point u = {20, 10}, v, w;
      v = u;
      v.x += 20;
      w = y;
      u.y += 10;
      u.x += 5;
      w.x -= 5;
      show(u);
                        show(v);
                        show(w);
                   }
Ans: Output is:
            25:20
            40:10
            35:10

 

Q .11. Rewrite the corrected code for the following program. Underline each correction.

#include<iostream.h>
structure club
{         
            int mem number;
            char memname[20];
            char memtype[] = “HELLO”;
};
void main( )
{
            club p1, p2;
            cin<<”Member Number:”;
            cin>>memnumber.p1;
            cout<<”Member Name:”;
            cin>>p1.membername;
            p1.memtype = “WORLD”;
            p2 = p1;
            cin<<”Member Number:”<<p2.memnumber;
            cin<<”Member Name:”<<p2.memname;
cin<<”Member Number;”<<p2.memtype;
}

Ans:

#include<iostream.h>
#include<string.h>
struct club
{         
            int memnumber;
            char memname[20];
            char memtype[6];
};
void main( )
{
            club p1, p2;
            cout<<”Member Number:”;
            cin>>p1.memnumber;
            cout<<”Member Name:”;
            cin>>p1.memname;
            strcpy(p1.memtype ,“WORLD”);
            p2 = p1;
            cout<<”Member Number:”<<p2.memnumber;
            cout<<”Member Name:”<<p2.memname;
cout<<”Member Type:”<<p2.memtype;
}

 

Previous | Next