Bubble Sort

Demonstration of Bubble Sort Concept

How can we sort an array?

In Bubble Sort, we take the simplest possible approach to sort an array.

• We look through the array in an orderly fashion, comparing only adjacent elements at a time.
• Whenever we see two elements which are out of order (refer to the picture below), we swap them so that the smaller element comes before the greater element.
• We keep performing the above steps over the array again and again till we get the sorted form.

When should we swap?

Important Observations

Let's take note of a few important observations :

• If we start from the first index and keep comparing the i^th and (i+1)^th element (where i varies from 1^th to the second last index), at the end of one iteration, we see that the greatest element in the entire array has reached the last position.
• This is because no matter where the greatest element was, it gets swapped repeatedly to reach it's correct position. Refer to the picture below!
• Similarly, if we do a second iteration, we will end up with the second greatest element in the second last position.

Step by Step Process for One Iteration