programming-for-dummies

396
Using Selection Sort
32 9 9 32 With a short list, bubble sort can work quickly.
Step #1
Step #2
74 32 21 9 With a long, unsorted list, bubble sort takes too much time.
32 74 21 9
Step #1
21 9 32 74
Step #5
32 21 74 9
Step #2
21 9 32 74
Step #6
Figure 1-2:
The bubble
sort
algorithm
examines
the entire
list of data
several
times.
32 21 9 74
Step #3
21 32 9 74
Step #4
9 21 32 74
Final sorted list
Using Selection Sort
Another simple way to sort a list is to search the entire list until you find the
smallest value. Then move that value to the front of the list. Now repeat the
process all over again, skipping the first item. By repetitively searching for
the smallest item and moving it to the front of the list, the selection sort
algorithm can eventually sort an entire list, as shown in Figure 1-3.
The selection sort algorithm works like this:
1. Find the smallest item in a list.
2. Swap this value with the value currently at the front of the list.
3. Repeat Steps 1 and 2 with the current size of the list minus one (list
size = list size – 1).