Review of S_LINK(search)

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

#define NODE_NUM 15

/* struct of the single link */
typedef struct _link
{
    int data;
    struct _link *next;
}S_LINK;

/*
 *get the length of a linklist
 * */
int get_link_len(S_LINK *link)
{
    S_LINK *p = link;
    int len = 0;

    while(NULL != p)
    {
        p = p->next;
        len += 1;
    }

    return len;

}


/* search from the linklist
 * find out the reversed k pos data
 * */
int search_posk(S_LINK *link,int k)
{
    printf("============SEARCH FROM LINKLIST===========\n");
    if(NULL == link)
    {
        printf("error:null linklist\n");
        exit(0);
    }

    S_LINK *tmp;
    int len;
    tmp = link;
    len = get_link_len(link);

    if(len < k)
    {
        printf("Error:k is larger than length\n");
        exit(0);
    }
    k = len - k;
    while(0 != (k--))
    {
        tmp = tmp->next;
    }

    if(NULL != tmp)
    {
        return tmp->data;
    }
    else
    {
        return 0;
    }

}

/**
 *create single link node
 **/
S_LINK *create_node(int data)
{
    S_LINK *tmp;
    tmp = (S_LINK*)malloc(sizeof(S_LINK));
    tmp->data = data;
    tmp->next = NULL;
    printf("create_node %d data:%d\n",data,data);
    return tmp;
}

/* print linklist */
void print_link(S_LINK *head)
{
    S_LINK *p = head->next;
    int i;

    printf("=============PRINT LINKLIST VALUE===========\n");
    while(NULL != p)
    {
        printf("%d-->",p->data);
        p = p->next;
    }

    printf("NULL\n");
}

int main()
{
    int i;
    S_LINK *linklist;//head node ptr
    S_LINK *node = NULL;
    S_LINK *move = NULL;

    linklist = (S_LINK *)malloc(sizeof(S_LINK));

    linklist->data = 0;
    linklist->next = NULL;
//    move = linklist;
    printf("head.data:%d\n",linklist->data);

    printf("=============SINGLE LINK CREATE==============\n");
    for(i = 0; i < NODE_NUM; i ++)
    {

        S_LINK *node;
        node  = create_node(i);
    //    printf("move->data:%d\n",move->data);
    //    printf("node->data:%d\n",node->data);
//        move->next = node;
        node->next = linklist->next;
        linklist->next = node;
    //    move = node;
    //    printf("i=%d,node.data:%d\n",i,node->data);

    }

    print_link(linklist);

    int ret = search_posk(linklist,3);
    printf("the reversed order pos %d node value is %d\n",3,ret);

    return 0;
}