연결 리스트 (문장<이름>)

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

typedef struct node NODE;
struct node
{
 char x[6];
 NODE *prev;
 NODE *next;
};

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 )
   if(node->next != tail)
   {
    node = node->next;
    continue;
   }
   else
    return node;
  if( strcmp(node->x,x) == 0 )
   return node;
  if( strcmp(node->x,x) > 0 )
  /*루트가 처음 head부터 돌기때문에 앞으로 검색은 필요없다..
  if(node->prev != head)
   {
    node = node->prev;
   }
   else
  */
    return node->prev;
 }

}

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(head == temp_node)
 {
  newnode->prev = head;
  newnode->next = head->next;
  head->next->prev = newnode;
  head->next  = newnode;
 }
 else
 {
  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;
 node = head->next;
 while(node != tail)
 {
  printf("%s\n",node->x);
  node = node->next;
 
 }

}

void x_swap(char *a,char *b)
{
 char tmp;
 tmp = *a;
 *a = *b;
 *b = tmp;
}

void main()
{

 char a='d';
 char b='r';
 x_swap(&a,&b);

 printf("%c\n%c\n",a,b);

 Insert_Node("dav");
 Insert_Node("cvd");
 Insert_Node("ass");
 Insert_Node("b'c'");
 Insert_Node("c");
 Insert_Node("css");
 Insert_Node("jlj");
 Insert_Node("권오철");
 Insert_Node("김건유");
 Insert_Node("홍정표");
 Insert_Node("이은미");
 Insert_Node("권혁신");
  Display();
 
}