This is the second part of a two-part article that explains how to use Quicksort. It is a method of sorting a list of elements and putting them in the correct order. Please make sure you have read and understood the first article before you read this one.
QuickSort in Action - Tackling a Sub-list (Page 3 of 6 )
We compare the left and right elements of the sub-list and then swap if necessary. The situation is as follows:
I
O
E
i
j
E
O
I
i
j
The left element, E, will be the pivot for the sub-list. We now increment i and decrement j under the same conditions as we did above. We end up with the following situation:
E
O
I
j
i
O is the first element for the variable index i that is higher than E. There is no element for the index variable j that is lower than E, so j ends at the position of E, the first position. We now exchange the left element, E, with the element of the position for j, which is still E. So E is exchanged with itself. The new value for the index variable k is now 0, which is the final position for E in the main list. The sub-list can now be written as:
(E0) [O I]
There is only one sub-list now, the right sub-list; there is no left sub-list. Whenever the computer (sorting program) arrives at the situation where there is no left sub-list, it starts sorting the immediate right sub-list, which in our case is [O I].
There are only two elements in the sub-list. We compare the left and right elements of the sub-list and then swap if necessary. The situation is as follows:
O
I
i
j
I
O
i
j
The left element, I, is the pivot for the sub-list. We now increment i and decrement j under the same conditions as we did above. We end up with the following:
I
O
j
i
O is the first element for the variable index i that is higher than I. There is no element for the index variable j that is lower than I, so j ends at the position of I. We now exchange the left element, I, with the element of the position for j, which is still I. So I is exchanged with itself. The new value for the index variable k is now 1, the position for I in the main list. The sub-list can now be written as:
(I1) [O]
Again, there is only one sub-list, the right sub-list; there is no left sub-list. Remember, whenever the computer (sorting program) arrives at the situation where there is no left sub-list, it starts sorting the immediate right sub-list, which in our case is [O]. There is only one element in this sub-list.
JavaScript 
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Sorting for Database Forms with HTML
