Page 681 - Computer science 868 Class 12
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SECTION – B
                                                          Answer any two questions.
                                Each program should be written in such a way that it clearly depicts the logic of the problem.
                                      This can be achieved by using mnemonic names and comments in the program.
                                                   (Flowcharts and Algorithms are not required.)
                                                      The programs must be written in Java.

                 Question 6.
                 Class name                                    :  Unique
                 Data members/instance variables:
                 num                                           :   to store a positive integer number
                 count                                         :   couints the number of digits in check_digit(int)
                 Methods/Member functions:
                 Unique()                                      :   default constructor to initialize the data member
                 void input_num()                              :   to accept a positive integer number
                 int count_digit(int d)                        :   returns the number of digits stored in d  from num using recursive
                 void check()                                  :    to check whether the given number is an Unique number or not depending
                                                                 on the value returned from count_digit(int). If the value returned is more
                                                                 than 1, then it is not an Unique Digit.
                   Specify the class Unique giving details of the constructor(), void input_num(), int count_digit(int) and void check(). Define a main()
                 function to create an object and call all the functions accordingly to enable the task.
                 Question 7:
                 A class Happy contains a two-dimensional array of order [m × n]. The maximum values possible for both ‘m’ and ‘n’ is 20. Design a class
                 Happy to fill the array with the first (m × n) Happy numbers in Rowwise.
                 The details of the members of the class are given below:
                 A happy number is a number in which the eventual sum of the square of the digits of the number is equal to 1.    [10]
                 Example:
                 28 = (2)∧2 + (8)∧2 = 4 + 64 = 68
                 68 = (6)∧2 + (8)∧2 = 36 + 64 = 100
                 100 = (1)∧2 + (0)∧2 + (0)∧2 = 1 + 0 + 0 = 1
                 Hence, 28 is a happy number.
                 Example:
                 12 = (1)∧2 + (2)∧2 = 1 + 4 = 5
                 Hence, 12 is not a happy number.
                 Design a class Happy to fill first m × n happy numbers in the array row wise. Some of the members of the class are given below:
                 Class name                                    :  Happy
                 Data Members/instance variables:
                 arr[][]                                       :   integer array to store the Happy numbers row wise
                 m                                             :   integer to store the number of rows
                 n                                             :   integer to store the number of columns
                 Happy(int mm, int nn)                         :   to initialise the size of the matrix, m=mm and n=nn
                 boolean ishappy(int)                          :    checks if the parameterised number is a happy number and returns true
                                                                 if it is a Happy number else returns false.
                 void fill()                                   :    to fill the elements of the array with the first (m × n) Happy numbers
                                                                 rowwise by invoking the ishappy(int) method.
                 void display()                                 :   to display the array in a matrix form
                 Specify the class Happy giving details of the Happy(int mm, int nn), boolean ishappy(int), void fill () and void display(). Also define a main()
                 function to create an object and call the methods.






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                                                                                            ISC Specimen Question Paper  679
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