Pairwise swap elements of a linked list by swapping data

Given a singly linked list, write a function to swap elements pairwise.

For example,

• If the linked list is 1->2->3->4->5 then the function should changeit to 2->1->4->3->5, and
• If the linked list is 1->2->3->4->5->6 then the function should change it to 2->1->4->3->6->5.

Algorithm:

• Set following pointers
  • prev = null
  • node = head
  • newHead = null
  • next = null
  • nextOfNext = null
• Iterate till node.next != null
  • next = node.next
  • nextOfNext = next.next
  • node.next = node
  • if (prev != null ) the pre.next = next
  • if (newHead == null) then newHead = next
  • prev = node
  • node = nextOfNext
• Return neHead

Latest Source Code:
Github: ListPairwiseSwap.java

Output:

1 2 
2 1 

1 2 3 4 5 6 
2 1 4 3 6 5 

1 2 3 4 5 6 7 
2 1 4 3 6 5 7