队列的C语言实现

头文件：Queue.h

typedef int BTDataType;
typedef struct BindaryTreeNode
{
	BTDataType data;
	struct BindaryTreeNode* left;
	struct BindaryTreeNode* right;
}BTNode;
typedef BTNode* QDataType;
typedef struct QueueNode
{
	QDataType data;
	struct QueueNode* next;
}QNode;
typedef struct Queue
{
	QNode* head;
	QNode* tail;
	int _size;
}Queue;
extern void QueueInit(Queue*);
extern void QueueDestroy(Queue*);
extern void QueuePush(Queue*,QDataType);
extern void QueuePop(Queue*);
extern QDataType QueueFront(Queue*);
extern QDataType QueueBack(Queue*);
extern bool QueueEmpty(Queue*);
extern int QueueSize(Queue*);

源文件：Queue.c 

#include"Queue.h"
void QueueInit(Queue* pq)
{
	assert(pq);
	pq->head = pq->tail = NULL;
	pq->_size = 0;
}
void QueueDestroy(Queue* pq)
{
	assert(pq);
	QNode* cur = pq->head;
	while (cur)
	{
		QNode* next = cur->next;
		free(cur);
		cur = next;
	}
	pq->head = pq->tail = NULL;
	pq->_size = 0;
}
void QueuePush(Queue* pq, QDataType data)
{
	assert(pq);
	QNode* newnode = (QNode*)malloc(sizeof(QNode));
	if (newnode == NULL)
	{
		perror("malloc fail");
		exit(EXIT_FAILURE);
	}
	else
	{
		newnode->data = data;
		newnode->next = NULL;
	}
	if (pq->head == NULL)
	{
		pq->head = pq->tail = newnode;
	}
	else
	{
		pq->tail->next = newnode;
		pq->tail = newnode;
	}
	pq->_size++;
}
void QueuePop(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	if (pq->head->next == NULL)
	{
		free(pq->head);
		pq->head = pq->tail = NULL;
	}
	else
	{
		QNode* next = pq->head->next;
		free(pq->head);
		pq->head = next;
	}
	pq->_size--;
}
QDataType QueueFront(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	return pq->head->data;
}
QDataType QueueBack(Queue* pq)
{
	assert(pq);
	assert(!QueueEmpty(pq));
	return pq->tail->data;
}
bool QueueEmpty(Queue* pq)
{
	assert(pq);
	return pq->head == NULL && pq->tail == NULL;
}
int QueueSize(Queue* pq)
{
	return pq->_size;
}