Page 662 - Computer science 868 Class 12
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(iv)  The following is a part of some class. What will the function mymethod( ) return when the value of the counter is equal to 5?
                      Show the dry run/working.                                                                     [3]

                      int  mymethod (int counter)
                      {
                      if (counter == 1)
                          return 1;
                      else
                      { return( (counter%10)%2= =0 ? counter%10* mymethod(counter – 1) :
                          mymethod(counter – 1) );
                       }
                       }
                  Ans.
                         mymethod(counter)  mymethod(5)   mymethod(4)    mymethod(3)   mymethod(2)    mymethod(1)
                       counter==0         false         false           false         false          return 1*2*4 =8
                       (counter%10)%2=0   5%10=5        4%10=4          3%10=3        2%10=2\
                                          5%2=0 false   4%2=0 true      3%2=0 false   2%2=0 true
                       return             mymethod(4)   4* mymethod(3)  mymethod(2)   2* mymethod(1)
                                                          PART II – 50 MARKS
                                          Answer six questions in this part, choosing two questions from
                                              Section A, two from Section B and two from Section C.
                                                            SECTION – A
                                                        Answer any two questions.
              Question 3.
                   (a)   Given the Boolean function F(A, B, C, D) = Σ(0, 2, 3, 4, 5, 8, 10, 11, 12, 13).
                      (i)   Reduce the above expression by using 4-variable Karnaugh map, showing the various groups (i.e. octal, quads and pairs).    [4]
                     Ans.
                                 C'.D'   C'.D    C.D   C.D'
                          A'.B'  1 0     0 1     1 3     1 2
                          A'.B  1 4      1 5     0 7     0 6
                          A.B    1    12   1    13   0    15   0    14
                          A.B'  1 8      0 9     1    11   1    10

                          Quad 1: m +m +m +m  = C'.D'
                                    4
                                 0
                                          12
                                       8
                          Quad 2: m +m +m +m  = B.C'
                                       12
                                    5
                                 4
                                           13
                          Quad 3: m +m +m +m  = B'.C
                                           11
                                    3
                                       10
                                 2
                          Quad 4: m +m +m +m  = B'.D' (redundant)
                                          10
                                       8
                                 0
                                    2
                          Reduced SOP expression is:
                          C'.D' + B.C' + B'.C
                      (ii)   Draw the Logic gate diagram of the reduced using AND/OR gates. Assume that the variables and it’s complements are
                         available as inputs                                                                        [1]
                     Ans.  The logic circuit diagram is
                         C'
                         D'
                         B'
                         C
                          B
                         C'

                660660  Touchpad Computer Science-XII
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