Double Queue linked list Src

Linked list를 이용한
Queue 테스트 코드

/*************************************************************************/                     
/*                                                                                                          */
/* Kernel Queue : Queue using Double linked list                                        */
/* program by juseok.yun                                                                        */
/* 2010.05.11                                                                                           */
/*************************************************************************/
#include <stdio.h>
// Double queue structur
typedef struct _dnode {
        char title[32];
        char name[32];
   struct _dnode *prev;  
        struct _dnode *next;
} DNODE;

// Make QUEUE Pointer
DNODE *queue_head=NULL, *queue_tail=NULL;

// initialize Queue
void init_queue(void)
{
 queue_head = (DNODE*)malloc(sizeof(DNODE));
 queue_tail = (DNODE*)malloc(sizeof(DNODE));
 queue_head->prev = queue_head;
 queue_head->next = queue_tail;
 queue_tail->prev = queue_head;
 queue_tail->next = queue_tail;
}

// Clear Queue
void clear_queue(void)
{
 DNODE *t_list = NULL;
 DNODE *s_list = NULL;
 t_list = queue_head->next;
 while (t_list != queue_tail)
 {
  s_list = t_list;
  t_list = t_list->next;
  free(s_list);
 }
 queue_head->next = queue_tail;
 queue_tail->prev = queue_head;
}

// Insert Data
// DNODE* member input
void enqueue(DNODE* member)
{
        DNODE* t_list = NULL;
       
//        if ( queue_head == NULL )
//        {
//           init_queue();
//        }
//        else
        {
   t_list = (DNODE*)malloc(sizeof(DNODE));
   memcpy(t_list->title,member->title,sizeof(member->title));
   memcpy(t_list->name,member->name,sizeof(member->name));
   queue_tail->prev->next = t_list;
   t_list->prev = queue_tail->prev;
   queue_tail->prev = t_list;
   t_list->next = queue_tail;
        }
}

// Get Data  De-queue
// DNODE* member output
DNODE* dequeue()
{
        DNODE* t_list = NULL;
        if ( queue_tail == NULL )
        {
           printf("Queue underflow.\n");
           return -1;
        }
       else
       {
   t_list = queue_head->next;
   if (t_list == queue_tail)
   {
    printf("\n  Queue underflow.");
    return -1;
   }
   queue_head->next = t_list->next;
   t_list->next->prev = queue_head;
   return t_list;
       }
}

// View data in queue
int view_queue()
{
        int i=0;
        DNODE* s_list = NULL;
        if ( queue_head == NULL )
  {
                return -1;
        }
       
        s_list = queue_head->next;
        while( s_list != queue_tail)
        {
                i++;
                printf("[%3d] Name : %s\t\t Title : %s\n",i,s_list->name,s_list->title);
                s_list = s_list->next;
        }
        // print the last
// don't need to display
//        i++;
//        printf("[%3d] Name : %s\t\t Title : %s\n",i,s_list->name,s_list->title);
       
       
        return 1;
}

main()
{
        DNODE* t_list;
        char t_name[32]={0,};
        char t_title[32]={0,};
        int ans=0;
        init_queue();
        while(ans != 4)
        {
                ans=0;
                printf("Queue Test Program\n");
                printf(" 1. Enqueue\n");
                printf(" 2. Dequeue\n");
                printf(" 3. View Queue\n");
                printf(" 4. Finish\n\n==> ");
               
                scanf("%d",&ans);
               
                switch(ans)
      {
                 case 1:
                         printf("Input Name(32byte) : ");
                         scanf("%s",t_name);
                         printf("Input Title (32byte) : ");
                         scanf("%s",t_title);
                         t_list=(DNODE*)malloc(sizeof(DNODE));
                         memcpy(t_list->name,t_name,sizeof(t_name));
                         memcpy(t_list->title,t_title,sizeof(t_title));
                         enqueue(t_list);
                         break;
                 case 2:
                         t_list = dequeue();
                         if ( t_list != NULL )
        {
                                 printf("Name : %s\n",t_list->name);
                                 printf("Title : %s\n",t_list->title);
                                 free(t_list);
                         }
        else
        {
                                 printf("There is no data\n");
                         }
                         break;
                 case 3:
                         if ( view_queue() == -1 )
        {
                                 printf("There is no data\n");
                         }
                         break;
                 case 4:
                         break;
                 default:
                         break;
                }
        }
  clear_queue();    
}

gcc -o queue queue.c

$> ./queue
Queue Test Program
1. Enqueue
2. Dequeue
3. View Queue
4. Finish

이렇게 실행됨..