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B.  Fill in the blanks:
                    1.  Fill in the blanks to print the sum of the digits of a number ‘num’ using the recursive method int sumofdigit(int n).
                       int sumofdigit(int n)
                       {
                           int dig;
                           if(a. …………………)
                               return b. …………………;
                           else
                           {
                               dig=c. …………………;
                               return dig + d. …………………;
                           }
                       }
                     2.  Fill in the blanks to return the product of all the numbers in an array using the recursive method.
                       int prod(int arr[],int i)
                        where arr[]={15, 3, 21, 7, 18} and i=0.
                       int prod(int arr[], int i)
                       {

                       if(a. …………………)
                           b. …………………;
                       else
                           c. …………………;
                       }
                    3.  Fill in the blanks to count the frequency of ‘A’ in a String using the recursive method int count(String s, int p)  where s="ABRACADABRA"
                       and p=0.
                       int count(String s, int p)
                       {
                        if(a. …………………)

                              b. …………………;
                           else if(c. …………………)

                              return 1+ d. …………………;
                           else
                              e. …………………;
                       }
                  Answers
                    1.  a. n==0          b.   0                c.   n%10                          d.  dig + sumofdigit(n/10)
                    2.  a. i==arr.length        b.   return 1        c.   return arr[i]*prod(arr,i+1)
                       3.   a. p==s.length()       b.   return 0        c.   s.charAt(p)==‘A’        d.   count(s,p+1)       e.  return count(s,p+1)

                 C.  Answer the following questions:
                    1.  Write two uses of recursion.
                   Ans.  Two uses of recursion are as follows:
                       •  Recursion is used extensively in the backtracking algorithm.
                       •  It can easily solve algorithms like tree traversal, tower of hanoi.




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