链式存储队列

#include <iostream>
#include <assert.h>
using namespace std;
typedef struct node
{
int data;
struct node *next;
}NODE;
typedef struct queue
{
NODE* head;
NODE* tail;
}QUEUE;
QUEUE* create_queue()
{
QUEUE* queue =  new QUEUE;
queue->head = NULL;
queue->tail = NULL;
return queue;
}
NODE* create_node(int data)
{
NODE* node = new NODE;
node->data = data;
node->next = NULL;
return node;
}
void queue_push(QUEUE* queue,int data)
{
NODE* node = create_node(data);
if(queue->tail == NULL)
{
queue->tail = node;
queue->head = node;
}
else
{
queue->tail->next = node;
queue->tail = node;
}
}
NODE* destroy_node(NODE* node)
{
NODE* next = node->next;
delete node;
return next;
}
int queue_pop(QUEUE* queue)
{
if(queue->head == NULL)
{
assert(false);
}
int data = queue->head->data;
queue->head =destroy_node(queue->head);
if(queue->head == NULL)
{
queue->tail = NULL;
}
return data;
}
int queue_size (QUEUE* queue)
{
int size = 0;
NODE* node = NULL;
for(node=queue->head; node;node=node->next)
{
size++;
}
return size;
}
void clear(QUEUE* queue)
{
while(queue->head)
{
queue->head = destroy_node(queue->head);
}
queue->tail = NULL;
}
void destroy_queue(QUEUE* queue)
{
clear(queue);
delete queue;
}
bool queue_empty(QUEUE* queue)
{
if( (queue->head==NULL) && (queue->tail==NULL))
{
return true;
}
return false;
}

int main()
{
QUEUE* queue = create_queue();
cout<<"input number:  ";
for(int i=0;i<10;i++)
{
queue_push(queue,i);
cout<<i<<" ";
}
cout<<endl;
//queue_pop(queue);  //
cout<<"output number:";
while(! queue_empty(queue))
{
cout<<queue_pop(queue)<<" ";
}
cout<<endl;
destroy_queue(queue);
return 0;
}