Page 151 - Information_Practice_Fliipbook_Class11
P. 151

For this purpose, we begin with a clean slate, i.e.,
            1.  We initialise reverseNum as 0.
            2.  Next, we extract the unit's digit (4) and add it to reverseNum. So, reverseNum becomes 4.
            3.   Now that we do not require the unit's digit any more, we discard it by setting num = num // 10. Now num is
                equal to 123.
            4.   Again, we multiply reverseNum by 10 and add to it the unit's digit (3) from the current value of num (123). Thus,
                reverseNum becomes 43. Again, discarding the units's digit of num, we get num equal to 12.
            5.   We multiply reverseNum by 10 and add to it the unit's digit (2) from the current value of num (12). Thus,
                reverseNum becomes 432. Now, discarding the units's digit (2) of num (12), we get the num equal to 1.
            6.   Again, we multiply reverseNum by 10 and add to it the unit's digit (1) from the current value of num (1). Thus,
                reverseNum becomes 4321.7. Now, discarding the units's digit of num, we get num equal to 0, which indicates
                that there are no more digits to be processed and we have been able to build reverseNum as desired.

            Program 6.6 Write a program to find reverse of the number.
              01 '''
              02 Objective: To find reverse of the number
              03 Input:
              04        num : number whose reverse has to be returned
              05 Output: reverse of num
              06 '''
              07 num = int(input('Enter a number: '))
              08 reverseNum = 0
              09 while num > 0:
              10     remainder = num % 10
              11     reverseNum = reverseNum * 10 + remainder
              12     num = num // 10
              13 print('Reverse: ', reverseNum)

            Sample Output:
             >>> Enter a number: 1234
                 Reverse: 4321
            As shown in the syntax for the while statement, it may include an optional else clause. It operates like the else
            clause in a for statement, i.e., the else clause gets executed on a smooth exit from the while loop. However, if control
            moves out of the while loop on execution of the break statement, the else clause is ignored.

                                                            Enter in loop
                                                                         False
                                                      Condition


                                                             True


                                                                             else block

                                                                       Body
                                                      Encounter
                                         no             break

                                                           yes

                                                Exit from loop
                                                             Fig 6.3




                                                                                              Looping in Python  137
   146   147   148   149   150   151   152   153   154   155   156