링크드리스트 관련하여 질문드립니다..ㅠㅠ 3일째 계속 진전이 없어 글올려봅니다!

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
struct record
{
    char name[3];
    char number[4];
    struct record * next;
};
 
#define POOL_SIZE 5
 
struct record pool[5];
struct record * top = pool;
struct record * tail = pool;
 
int compare(char key[3], struct record *);
 
struct record * data = NULL; 
 
 
void init_pool() 
{
    printf("init_pool()\n");
    int i;
    struct record *r = pool;
    struct record *s;
 
    strcpy(pool[0].name, "tt");
    strcpy(pool[1].name, "bt");
    strcpy(pool[2].name, "st");
    strcpy(pool[3].name, "wt");
 
 
    pool[POOL_SIZE - 1].next = NULL;
 
    for (i = 1; i<POOL_SIZE; i++) 
    {
        s = r++;
	s->next = r;
        printf("s:%x r:%x   s:%s r:%s\n", s, r, s->name, r->name);
    }
}
 
//pop
struct record * newnode()
{
    printf("record * newnode()\n");
    struct record* r;
    if (top == NULL) 
    {
	printf("Pool is empty. Bye!\n");
    }
    r = top;
    top = r->next;
    printf("r:%x top:%x    r:%s top:%s\n", r, top, r->name, top->name);
    return r;
}
 
// Push
void freenode(struct record *r)
{
    printf("freenode(struct record *r)\n");
    r->next = top;
    top = r;
    printf("r:%x top:%x    r:%s top:%s\n", r, top, r->name, top->name);
}
 
void add(char *name, char *number)
{
    printf("add(char *name, char *number)\n");
    tail = tail->next;
    struct record * r = tail;
    strcpy(r->name, name);
    strcpy(r->number, number);
 
    r = top;
    int i;
    struct record *s;
    for (i = 1; i<POOL_SIZE; i++) 
    {
        s = r++;
	s->next = r;
        printf("s:%x r:%x    s:%s r:%s\n", s, r, s->name, r->name);
    }
}
 
int compare(char key[3], struct record *r)
{
    if (r == NULL)
        return -1;
    else
	return strncmp(key, r->name, 3);
}
 
int main()
{
    init_pool();
    struct record * r = newnode();
    freenode(r);
    newnode();
    add("ab","123");
    add("cd","456");
    add("ef","789");
 
    return 0;
}
 
//
init_pool()
s:8049b20 r:8049b2c   s:tt r:bt
s:8049b2c r:8049b38   s:bt r:st
s:8049b38 r:8049b44   s:st r:wt
s:8049b44 r:8049b50   s:wt r:
record * newnode()
r:8049b20 top:8049b2c    r:tt top:bt
freenode(struct record *r)
r:8049b20 top:8049b20    r:tt top:tt
record * newnode()
r:8049b20 top:8049b2c    r:tt top:bt
add(char *name, char *number)
s:8049b2c r:8049b38    s:ab r:st
s:8049b38 r:8049b44    s:st r:wt
s:8049b44 r:8049b50    s:wt r:
s:8049b50 r:8049b5c    s: r:
add(char *name, char *number)
s:8049b2c r:8049b38    s:ab r:cd
s:8049b38 r:8049b44    s:cd r:wt
s:8049b44 r:8049b50    s:wt r:
s:8049b50 r:8049b5c    s: r:
add(char *name, char *number)
s:8049b2c r:8049b38    s:ab r:cd
s:8049b38 r:8049b44    s:cd r:ef
s:8049b44 r:8049b50    s:ef r:
s:8049b50 r:8049b5c    s: r: