연결 리스트 (한 글자)

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

typedef struct node NODE;
typedef struct node
{
 char x[3];
 NODE *prev;
 NODE *next;
}NODE;

NODE *head = NULL;
NODE *tail = NULL;

NODE* Find_Node(char *x)
{
 NODE *node;
 node = (NODE*)malloc(sizeof(NODE));
 node = head->next;
 while(node != tail)
 {
  if( strcmp(node->x,x) < 0)
   return node;
  else if( strcmp(node->x,x) == 0)
   return node;
  else if( strcmp(node->x,x) > 0  )
   return node->prev;
 
 }
  return node;
}

int Insert_Node(char *x)
{
 NODE *newnode;
 newnode = (NODE*)malloc(sizeof(NODE));
 strcpy(newnode->x , x);
 if(head == tail)
 {
  head = (NODE*)malloc(sizeof(NODE));
  tail = (NODE*)malloc(sizeof(NODE));
  newnode->prev = head;
  newnode->next = tail;
  head->next = newnode;
  tail->prev = newnode;
  head->prev = NULL;
  tail->next = NULL;
 
  return 0;
 }
 NODE *temp_node = Find_Node(x);
 if(!temp_node)
 {
  newnode->prev = head;
  newnode->next = head->next;
  head->next->prev = newnode;
  head->next  = newnode;
 }
 else
 {
  temp_node = Find_Node(x);
  newnode->prev = temp_node;
  newnode->next = temp_node->next;
  temp_node->next->prev = newnode;
  temp_node->next = newnode;
 }
 return 0;
}

int Delet_Node(char x)
{
 return 0;
}

void Display()
{
 NODE *node;
 node = (NODE*)malloc(sizeof(NODE));
 if( !head )
  return;
 while(node != tail)
 {
  printf("%c\n",node->x);
  node = node->next;
 
 }

}
void main()
{
 Insert_Node('a');
 Insert_Node('b');
 Insert_Node('d');
 Insert_Node('c');
 Insert_Node('s');
 Insert_Node('h');
 Insert_Node('d');
 Display();
}