Iteratively Reverse a linked list using only 2 pointers (An Interesting Method)

Given pointer to the head node of a linked list, the task is to reverse the linked list.

Examples: 

Input : Head of following linked list 
 1->2->3->4->NULL
Output : Linked list should be changed to,
 4->3->2->1->NULL

Input : Head of following linked list 
 1->2->3->4->5->NULL
Output : Linked list should be changed to,
 5->4->3->2->1->NULL

We have seen how to reverse a linked list in article Reverse a linked list. In iterative method we had used 3 pointers prev, cur and next. Below is an interesting approach that uses only two pointers. The idea is to use XOR to swap pointers. 

Given linked list
85 15 4 20 
Reversed Linked list 
20 4 15 85

Time Complexity: O(n) 
Auxiliary Space: O(1) since using space for prev and next

Alternate Solution : 

Given linked list
85 15 4 20 
Reversed Linked list 
20 4 15 85

Time Complexity : O(n) 
Auxiliary Space: O(1)

Thanks to Abhay Yadav for suggesting this approach.