Example of a linked list using void pointers rather than specified data types

linked.c

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

struct node {
    void *data;
    struct node* next;
};


/* Tack a value onto the end of the list, returning the head */
struct node *append(struct node *head, void *data) {
    struct node *new_node = NULL;

    if( !head ){
        new_node = (struct node *) malloc( sizeof( struct node ) );
        new_node->next = NULL;
        new_node->data = data;
        return new_node;
    }

    head->next = append( head->next, data );
    return head;
}


/* Retrieve the data at the specified index */
void *get( struct node *head, int index ) {

    if( index == 0 ) {
        return head->data;
    }

    return get( head->next, index-1 );
}


/* Release memory used by the list */
void free_list( struct node *head ) {
    if( head ){
        free_list( head->next );
        free( head );
    }
}


int main() {

    int values[] = { 1, 2, 3 };
    struct node *list = NULL;

    list = append( list, values );
    list = append( list, &values[1]  );
    list = append( list, &values[2]  );

    /* Print the list we built */
    int i;
    for( i = 0; i < 3; i++ ){
        printf("%d\n", *(int *) get(list, i));
    }

    free_list( list );

    return 0;
}