Page 279 - computer science (868) class 11
P. 279

Let us take the following example.
                 The array is to be sorted in ascending order:

                                     Index         0          1           2           3           4
                                       Ar         27          16          12         10          21

                 Step 1:  Find the smallest element.
                                     Index         0          1           2           3           4

                                       Ar         27          16          12         10          21
                        The smallest element is in position ar[3]: 10. Interchange this number with the first element.

                        After swapping ar[0] and ar[3], the array becomes:
                                     Index         0          1           2           3           4

                                       Ar         10          16          12         27          21
                        After the first step, the smallest element is stored in the first position of the array.

                 Step 2:  Find the next smallest number.
                                     Index         0          1           2           3           4

                                       Ar         10          16          12         27          21
                        The second smallest element is in position ar[2]: 12. Interchange this number with the second element.

                        After swapping ar[1] and ar[2], the array becomes:
                                     Index         0          1           2           3           4

                                       Ar         10          12          16         27          21
                        After the second step, the second smallest element is stored in the second position of the array.

                 Step 3:  Find the next smallest number.
                                     Index         0          1           2           3           4

                                       Ar         10          12          16         27          21
                        The third smallest element is in position ar[2]: 16. Interchange this number with the third element.

                        After the third step, the third smallest element is already stored in the third position of the array.
                 Step 4:  Find the next smallest number.

                                     Index         0          1           2           3           4

                                       Ar         10          12          16         27          21
                        The fourth smallest element is in position ar[4]: 21. Interchange this number with the fourth element.

                        After swapping ar[3] and ar[4], the array becomes:
                                     Index         0          1           2           3           4

                                       Ar         16          12          16         21          27
                        After the fourth step, the array has been sorted in ascending order.

                 We can clearly see that the selection sort technique performs a smaller number of swaps as compared to the bubble
                 sort technique. Thus, it performs faster and more efficiently than the bubble sort.



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