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implementing a queue of structure

zigla
zigla asked
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Last Modified: 2010-04-15
i would like to get help on how to implement a FIFO queue of data structures using c. i would like to use it as an entry point in my program i am currently coding for tcp/ip routing program. It should have a menu.I would appreciate if i got help soon .I am a student at the university.
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Commented:
Edited text of question
what does the menu have to do with the fifo queue ?
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ecw

Commented:
Answers2000.  You've implemented a LIFO.  You're adding to the front of the list and removing from the front.  Try something like:

#include <assert.h>
#include <malloc.h>

struct queue_item {
  void *data;
  struct queue_item *next;
};

typedef struct queue *Queue;
struct queue {
  struct queue_item *head;
  struct queue_item *last;
} ;

Queue Queue_create(void)
{
Queue queue = calloc((size_t) 1, sizeof(*queue));
  return queue;
}

void *Queue_add_item(Queue queue, void *data)
{
struct queue_item *item;

  assert(queue != 0);

  if ((item = malloc(sizeof(*item)))) {
   item-> data = data;
   item-> next = 0;
   if (! queue-> head) {
     queue-> head = queue-> last = item;
   } else {
     queue-> last = queue-> last-> next = item;
   }
  }
  return item;
}

void *Queue_get_head(Queue queue)
{
struct queue_item *next = 0;
void *data = 0;
  assert(queue != 0);
  if (queue-> head) {
    data = queue-> head-> data;
    next = queue-> head-> next;
    free(queue-> head);
    if (! (queue-> head = next)) {
      queue-> last = 0;
    }
  }
  return data;
}

Zigla: I don't see how a menu relates to a FIFO queue though.  Can you elaborate on the problem a little bit more, please?
OOps ecw is right, misread the question.  Not tried his code
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