Найти ошибку в коде - C (СИ) (73397)

#include <stdlib.h>
#include <stdio.h>
#include <malloc.h>
 
typedef struct node
{
    int  num;
    struct node *next;
    struct node *Prev;
} Node;
Node *init()
{
    int i;
    Node *ptr = (Node*)calloc(10, sizeof(Node));
    for (i = 1; i <= 10; i++, ptr->next)
    {
        ptr->num = 1;
        ptr->next = NULL;
    }
 
}
int main()
{
    Node *head;
    head = 0;
    head->num = 1;
    head->next = NULL;
    head->Prev = NULL;
    return 0;
}