// Java program to pairwise swap elements of a linked list
class LinkedList
{
	Node head; // head of list

	/* Linked list Node*/
	class Node
	{
		int data;
		Node next;
		Node(int d) {data = d; next = null; }
	}

	void pairWiseSwap(Node prev, Node current)
	{
		if(current != null && current.next!=null){
		    Node temp=current.next;
		    current.next=current.next.next;
		    temp.next=current;
		    if(prev!=null){
		        prev.next=temp;
		    }else{
		        head=temp;
		    }
		    
		}else{
		    return;
		}
     pairWiseSwap(current,current.next);

	}

					
	/* Utility functions */

	/* Inserts a new Node at front of the list. */
	public void push(int new_data)
	{
		/* 1 & 2: Allocate the Node &
				Put in the data*/
		Node new_node = new Node(new_data);

		/* 3. Make next of new Node as head */
		new_node.next = head;

		/* 4. Move the head to point to new Node */
		head = new_node;
	}

	/* Function to print linked list */
	void printList()
	{
		Node temp = head;
		while (temp != null)
		{
		System.out.print(temp.data+" ");
		temp = temp.next;
		} 
		System.out.println();
	}

	/* Driver program to test above functions */
	public static void main(String args[])
	{
		LinkedList llist = new LinkedList();

		/* Created Linked List 1->2->3->4->5 */
		llist.push(5);
		llist.push(4);
		llist.push(3);
		llist.push(2);
		llist.push(1);
		
		System.out.println("Linked List before calling pairWiseSwap() ");
		llist.printList();
		
		llist.pairWiseSwap(null,llist.head);
		
		System.out.println("Linked List after calling pairWiseSwap() ");
		llist.printList();
	}
} 
/* This code is contributed by Rajat Mishra */

@@ -1589,51 +1589,5 @@
 %0A%7D %0A
-/* This code is contributed by Rajat Mishra */
 %0A

Update PairwiseSwapElementsOfAGivenLinkedList.java