程序代码：

#include<stdio.h>

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

struct node* create_node(int data)
{
    struct nodet *p;
        p = head;
        char s = ' ';
        if (head == NULL) {
            printf("?????");
        }
        if (head != NULL) {
            do {
                printf("%c%c%d", s, s, p->data);
                p = p->next;
            } while (p != NULL);
            printf("\n");
        }
    
    
    
    //You write here ...
}

void add_to_list(struct node* list, int data)
{

    struct node *head;
        struct node *p1, *p2;
        int n = 0;
        p1 = p2 = (struct node*)malloc(sizeof(struct node));
        scanf("%d", &p1->num);
        head = NULL;
        while (p1->num != 0) {
            n = n + 1;
            if (n == 1)
                head = p1;
            else
                p2->next = p1;
            p2 = p1;
            p1 = (struct node*)malloc(sizeof(struct node));
            scanf("%d", &p1->num);


    //You write here ...
}

int search(struct node* list, int data)
{
    int *p;
        for (p = node; p< node + data; p++) //??????
            if (*p == key)
                return p - node;
        return -1;
    //You write here ...
}