数据结构（链式队列）（C语言）

利用C语言实现链式队列的基本功能：

• 头文件：

#ifndef _LINKQUEUE_H_
#define _LINKQUEUE_H_

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

#define SUCCESS   100
#define FAILURE   101
#define TRUE      102
#define FALSE     103

typedef int DataType;

typedef struct node
{
	DataType data;
	struct node *next;
}Node;

typedef struct queue
{
	Node *front;
	Node *rear;
}Queue;

int QueueInit(Queue **queue);
int QueueInsert(Queue *queue, DataType e);
int QueueDelete(Queue *queue);
int GetTop(Queue *queue);
int QueueEmpty(Queue *queue);
int QueueClear(Queue *queue);
int QueueDestory(Queue **queue);

#endif

• 功能函数：

#include "LinkQueue.h"

int QueueInit(Queue **queue)
{
	if(NULL == queue)
	{
		return FAILURE;
	}
	
	*queue = (Queue *)malloc(sizeof(Queue));
	if(NULL == *queue)
	{
		return FAILURE;
	}
	
	Node *p = (Node *)malloc(sizeof(Node));
	if(NULL == p)
	{
		return FAILURE;
	}
	p->next = NULL;
	
	(*queue)->front = p;
	(*queue)->rear = p;
	
	return SUCCESS;
}

int QueueInsert(Queue *queue, DataType e)
{
	if(NULL == queue)
	{
		return FAILURE;
	}
	
	Node *p = (Node *)malloc(sizeof(Node));
	if(NULL == p)
	{
		return FAILURE;
	}
	
	p->data = e;
	p->next = NULL;
	
	queue->rear->next = p;
	queue->rear = p;
	
	return SUCCESS;
}

int QueueDelete(Queue *queue)
{
	if(NULL == queue || queue->front->next == NULL)
	{
		return FAILURE;
	}
	
	DataType e = queue->front->next->data;
	Node *p = queue->front->next;
	queue->front->next = p->next;
	free(p);
	
	if(queue->front->next == NULL)
	{
		queue->rear = queue->front;
	}
	
	return e;
}

int GetTop(Queue *queue)
{
	if(NULL == queue || queue->front->next == NULL)
	{
		return FAILURE;
	}
	
	return queue->front->next->data;
}

int QueueEmpty(Queue *queue)
{
	if(NULL == queue)
	{
		return FAILURE;
	}
	
	return (queue->rear == queue->front) ? TRUE : FALSE;
}

int QueueClear(Queue *queue)
{
	if(NULL == queue)
	{
		return FAILURE;
	}
	
	Node *p = queue->front->next;
	while(p)
	{
		queue->front->next = p->next;
		free(p);
		p = queue->front->next;
	}
	
	queue->rear = queue->front;
	
	return SUCCESS;
}

int QueueDestory(Queue **queue)
{
	if(NULL == queue || *queue == NULL)
	{
		return FAILURE;
	}
	
	Node *p = (*queue)->front->next;
	while(p)
	{
		(*queue)->front->next = p->next;
		free(p);
		p = (*queue)->front->next;
	}
	
	(*queue)->rear = (*queue)->front;
	free((*queue)->rear);
	free(*queue);
	
	return SUCCESS;
}

• 测试主函数：

#include "LinkQueue.h"

int main()
{
	Queue *queue = NULL;
	int ret, i;
	
	ret = QueueInit(&queue);
	if(SUCCESS == ret)
	{
		printf("Init Success.\n");
	}
	else
	{
		printf("Init Failure.\n");
	}
	
	for(i = 0; i < 9; i++)
	{
		ret = QueueInsert(queue, i);
		if(SUCCESS == ret)
		{
			printf("QueueInsert %d Success.\n", i);
		}
		else
		{
			printf("QueueInsert %d Failure.\n", i);
		}
	}
	
	for(i = 0; i < 4; i++)
	{
		ret = QueueDelete(queue);
		if(FAILURE == ret)
		{
			printf("QueueDelete Failure.\n");
		}
		else
		{
			printf("QueueDelete %d Success.\n", ret);
		}
	}
	
	ret = GetTop(queue);
	if(FAILURE == ret)
	{
		printf("Get Top Failure.\n");
	}
	else
	{
		printf("Queue Top is %d.\n", ret);
	}
	
	ret = QueueEmpty(queue);
	if(TRUE == ret)
	{
		printf("Queue is Empty.\n");
	}
	else if(FALSE == ret)
	{
		printf("Queue is not Empty.\n");
	}
	else if(FAILURE == ret)
	{
		printf("ERROR.\n");
	}
	
	ret = QueueClear(queue);
	if(SUCCESS == ret)
	{
		printf("QueueClear Success.\n");
	}
	else
	{
		printf("QueueClear Failure.\n");
	}
	
	ret = QueueDestory(&queue);
	if(SUCCESS == ret)
	{
		printf("QueueDestory Success.\n");
	}
	else
	{
		printf("QueueDestory Failure.\n");
	}
	
	
	return 0;
}