double linked list with XOR

linked_list.c

#include<stdlib.h>
#include<stdio.h>

struct Node {
  int data;
  struct Node *both;
};

// https://stackoverflow.com/a/26569748
struct Node * xor(struct Node *m, struct Node *n){
  return (struct Node *)((uintptr_t)m ^ (uintptr_t)n);
}

struct Node *head = NULL;
struct Node *previous = NULL;
struct Node *current = NULL;

void add(int data) {
  //create a link
  struct Node *link = (struct Node*) malloc(sizeof(struct Node));
	
  link->data = data;
  if(head == NULL){
    link->both = NULL;
    head = link;
    current = link;
  }
  else{
    link->both = xor(current,NULL);
    current->both = xor(previous,link);
    previous = current;
    current = link;
  }
}

struct Node * get(int wantedIndex){
  struct Node *node = head;
  struct Node *prev = NULL;
  struct Node *temp = NULL;
  int i = 0;
  while(node != NULL){
    if(wantedIndex == i){
      return node;
    }
    i++;
    temp = node;
    node = xor(prev,node->both);
    prev = temp;
  }
  return NULL;
}

void printLinkedList(){
  struct Node *node = head;
  struct Node *prev = NULL;
  struct Node *temp = NULL;
  while(node != NULL){
    printf("%d\t",node->data);
    temp = node;
    node = xor(prev,node->both);
    prev = temp;
  }
}

int main()
{
  add(5);
  add(7);
  add(8);
  add(9);
  add(11);
  printLinkedList();
  return 0;
}