xored linked list

xorlinkedlist.c

// =====================================================================================
//
//       Filename:  xorlinked.c
//
//    Description:  
//
//        Version:  1.0
//        Created:  04/13/2014 09:51:25 PM
//       Revision:  none
//       Compiler:  gcc
//
//         Author:  Halit Alptekin (), [email protected]
//   Organization:  
//
// =====================================================================================
#include <stdio.h>
#include <stdlib.h>

struct Node {
    struct Node* np;
    void* data;
};

struct List {
    struct Node* head;
    unsigned int size;
};

struct List* init_list(){
    struct List* new_list = (struct List*)malloc(sizeof(struct List));
    new_list->size = 0;
    new_list->head = NULL;

    return new_list;
}

struct Node* xor_op(struct Node* first, struct Node* last){
    return (struct Node*)((unsigned int)first ^ (unsigned int)last);
}

void add_elem(struct List* list, void* elem){
    struct Node* new_node = (struct Node*)malloc(sizeof(struct Node));
    new_node->np = xor_op(list->head, NULL);
    new_node->data = elem;
 
    if(list->head){
        struct Node* next_node = xor_op(list->head->np, NULL);
        list->head->np = xor_op(new_node, next_node);
    }
    
    list->head = new_node;
    list->size++;
}

void print_list(struct List* list){
    struct Node* cur = list->head;
    struct Node* prev = NULL;
    struct Node* next;
    while(cur){
        printf("%d ", (int)cur->data);
        next = xor_op(prev, cur->np);
        prev = cur;
        cur = next;
    }
}

int main(int argc, const char *argv[]){
    struct List* my_list = init_list();
    add_elem(my_list, (void*)5);
    add_elem(my_list, (void*)6);
    add_elem(my_list, (void*)7);

    print_list(my_list);
    
    return 0;
}