CBSE Class 12 Computer Science Marking Scheme (All India): 2017

1(a)

Write the type of C++ tokens (keywords and user defined identifiers) from the

following:

(i) new

(ii) While

(iii) case

(iv) Num_2

Ans

(i) new - Keyword

(ii) While - User defined Identifier

(iii) case - Keyword

(iv) Num_2 - User defined Identifier

(b)

Anil typed the following C++ code and during compilation he found three errors

as follows:

(i) Function strlen should have prototype

(ii) Undefined symbol cout

(iii) Undefined symbol endl

On asking, his teacher told him to include necessary header files in the code.

Write the names of the header files, which Anil needs to include, for successful

compilation and execution of the following code

void main()

{

char Txt[] = "Welcome";

for(int C= 0; C<strlen(Txt); C++)

Txt[C] = Txt[C]+1;

cout<<Txt<<endl;

}

CBSE Board Exam 2018: Copy Checking Process vs Expected Marks in Class 12

Ans

string.h

iostream.h OR fstream.h OR iomanip.h

(½ Mark each for writing correct header files)

NOTE:

Ignore additional header file(s)

(c)

Rewrite the following C++ code after removing any/all syntactical errors

with each correction underlined.

Note: Assume all required header files are already being included in the

program.

void main()

{

cout<<"Enter an Alphabet:";

cin>>CH;

switch(CH)

case ‘A’ cout<<"Ant"; Break;

case ‘B’ cout<<"Bear" ; Break;

}

void main()

{

cout<<"Enter an Alphabet:";

char CH;                            // Error 1

cin>>CH;

switch(CH)

{                                          // Error 2(i)

case ‘A’ :                          // Error 3(i)

cout<<"Ant"; break;     // Error 4(i)

case ‘B’ : // Error 3(ii)

cout<<"Bear"; break;  // Error 4(ii)

}                                      // Error 2(ii)

}

(½ Mark for correcting Error 1)

(½ Mark for correcting Error 2(i) and Error 2(ii))

(½ Mark for correcting Error 3(i) and Error 3(ii))

(½ Mark for correcting Error 4(i) and Error 4(ii))

OR

(1 Mark for identifying all the errors without corrections)

(d)

Find and write the output of the following C++ program code:

Note: Assume all required header files are already included in the

program.

#define Diff(N1,N2) ((N1>N2)?N1-N2:N2-N1)

void main()

{

int A,B,NUM[] = {10,23,14,54,32};

for(int CNT =4; CNT>0; CNT--)

{

A=NUM[CNT];

B=NUM[CNT-1];

cout<<Diff(A,B)<<'#';

}

}

Ans

22#40#9#13#

(½ Mark for writing each correct value)

OR

(1 Mark to be awarded if the output written in reverse order as

13#9#40#22#)

Note: Deduct ½ Mark for not considering any/all # as separator and/or

writing the values in different lines

(e)

Find and write the output of the following C++ program code:

Note: Assume all required header files are already being included

in the program.

void main()

{

         int *Point, Score[]={100,95,150,75,65,120};

         Point = Score;

         for(int L = 0; L<6; L++)

{

          if((*Point)%10==0)

          *Point /= 2;

          else

          *Point -= 2;

           if((*Point)%5==0)

           *Point /= 5;

            Point++;

}

             for(int L = 5; L>=0; L--)

             cout<<Score[L]<<"*";

}

Ans

12*63*73*15*93*10*

(½ Mark for writing each correct value)

Note:

● Deduct ½ Mark for not considering any/all * as separator and or writing the values in different lines

● Deduct ½ Mark if the output written in reverse order as

10*93*15*73*63* 12*

● Full 3 Marks to be awarded if “Multiple declaration/syntax error for L” is mentioned