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

struct list {
    int node;
    struct list *next;
};

int sum(const struct list *x) {
    if (x == NULL)
        return 0;
    else
        return x->node + sum(x->next);
}

int main(void) {
    /* Is there no shorter way? */
    struct list node3 = { 3, NULL };
    struct list node2 = { 2, &node3 };
    struct list node1 = { 1, &node2 };
    struct list *llist = &node1;

    printf("%d\n", sum(llist));
    /* Just to make sure llist wasn't modified. */
    printf("%d\n", sum(llist)); 

    return EXIT_SUCCESS;
}