Question

Write an algorithm for bubble sort with suitable example.

Answer 1

Here, DATA is a linear array with N elements. This algorithm sorts the elements of DATA in ascending order.

Step 1: Repeat steps 2 and 3 for K = 1 to N – 1

Step 2: Set Ptr: = 1

Step 3: Repeat while Ptr ≤ N – K

1. If DATA[Ptr] > DATA[Ptr + 1], then interchange DATA[Ptr] and DATA[Ptr + 1]
2. Set Ptr := Ptr + 1

Step 4: Exit

After N – 1 passes, all elements are sorted.

Example:

Consider a linear array of 5 elements:

Data[1] = 55
Data[2] = 43
Data[3] = 05
Data[4] = 06
Data[5] = 09

Pass 1:
55 > 43 → swap → 43 55 5 6 9
55 > 5 → swap → 43 5 55 6 9
55 > 6 → swap → 43 5 6 55 9
55 > 9 → swap → 43 5 6 9 55

The largest element, 55, moves to the last position.

Pass 2:
43 > 5 → swap → 5 43 6 9 55
43 > 6 → swap → 5 6 43 9 55
43 > 9 → swap → 5 6 9 43 55

Second largest element 43 moves to the correct position.

Pass 3:
5 < 6 → no swap
6 < 9 → no swap

Final sorted list:
5 6 9 43 55

After N – 1 passes, the array is sorted in ascending order.