#include <stdlib.h>     //NULL, malloc
#include <stdio.h>      //printf
#include <assert.h>     //assert
 
typedef struct Node {
    int val;
    struct Node* next;
} node;
 
node* make_ll(int len){
    node head;  // Code only populates the next field.
    head.next = NULL;
    node* cur = &head;
    for (int i = 0; i < len; i++) {
        cur->next = malloc(sizeof *(cur->next));
        assert(cur->next);
        cur = cur->next;
        cur->val = i;
        cur->next = NULL;
    }
    return head.next;
}
 
void print_ll(const node* head){
    const node* cur = head;
    while (cur != NULL) {
        printf("Node %d @ %p points to %p as next\n",
                cur->val, (const void *) cur, (void *) cur->next);
        cur = cur->next;
    }
}
 
int main(){
    node* ll = make_ll(4);
    print_ll(ll);
    free(ll);
}

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