队列（链式）

教材：严版数据结构

代码如下：

#include<stdio.h>
#include<stdlib.h>
#include<iostream>
 
using namespace std;
#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define OVERFLOW -2
typedef int Status;
typedef int QElemType;
typedef struct QNode
{
	QElemType data;
	struct QNode *next;
}QNode,*QueuePtr;
 
typedef struct
{
	QueuePtr front;//队头指针
	QueuePtr rear;//队尾指针
}LinkQueue;
 
Status InitQueue(LinkQueue &Q)
{
	Q.front = Q.rear = (QueuePtr)malloc(sizeof(QNode));
	if (!Q.front)
		exit(OVERFLOW);
	Q.front->next = NULL;
	return OK;
}
 
Status DestroyQueue(LinkQueue &Q)//销毁队列
{
	while (Q.front) {
		Q.rear = Q.front->next;
		free(Q.front);
		Q.front = Q.rear;
	}
	return OK;
}
 
Status CLearQueue(LinkQueue &Q)//清空队列
{
	QueuePtr p, q;
	if (!Q.front)
		exit(OVERFLOW);
	p = Q.front->next;
	Q.front->next = NULL;
	while (p)
	{
		q = p;
		p = p->next;
		free(q);
	}
	Q.rear = Q.front;
	return OK;
}
 
Status QueueEmpty(LinkQueue Q)
{
	if (Q.rear == Q.front)
		return TRUE;
	else
		return FALSE;
}
 
int QueueLength(LinkQueue Q)
{
	QueuePtr p;
	int n = 0;
	p = Q.front->next;
	while (p)
	{
		n++;
		p = p->next;
	}
	return n;
}
 
Status GetHead(LinkQueue Q, QElemType &e)
{
	QueuePtr p;
	if (Q.front == Q.rear)
		return ERROR;
	p = Q.front->next;
	e = p->data;
	return OK;
}
 
Status EnQueue(LinkQueue &Q, QElemType e)
{
	QueuePtr p;
	p = (QueuePtr)malloc(sizeof(QNode));
	if (!p)
		exit(OVERFLOW);
	p->data = e;
	p->next = NULL;
	Q.rear->next = p;
	Q.rear = p;
	return OK;
}
 
Status DeQueue(LinkQueue &Q, QElemType &e)
{
	QueuePtr p;
	if (Q.front == Q.rear)
		return ERROR;
	p = Q.front->next;
	e = p->data;
	Q.front->next = p->next;
	if (Q.rear == p)
		Q.rear = Q.front;
	free(p);
	return OK;
}
 
Status QueueTraverse(LinkQueue &Q)
{
	QueuePtr p = Q.front->next;
	if (p == NULL)
		return ERROR;
	while (p)
	{
		printf("%d ", p->data);
		p = p->next;
	}
	printf("\n");
	return OK;
}
 
void main()
{
	int i, n;
	QElemType k, h, a, f;
	LinkQueue Q;
	printf("创建一个空队列！\n");
	InitQueue(Q);
	printf("判断队列是否为空!\n");
	printf("QueueEmpty(Q)=%d\n", QueueEmpty(Q));
	printf("创建队列的元素个数：\n");
	cin >> n;
	printf("输入%d个插入队列的元素的值：\n", n);
	for (i = 0; i < n; i++)
	{
		cin >> k;
		EnQueue(Q, k);
	}
	printf("输出队列元素的值：\n");
	QueueTraverse(Q);
	printf("输入插入队列的元素的值：");
	cin >> h;
	EnQueue(Q, h);
	printf("输入插入一个队列元素后队列元素的值：");
	QueueTraverse(Q);
	DeQueue(Q, a);
	printf("输入第1个删除的队头元素的值：%d\n", a);
	DeQueue(Q, a);
	printf("输入第2个删除的队头元素的值：%d\n", a);
	printf("输出两次删除队头元素后队列的元素值：");
	QueueTraverse(Q);
	if (!GetHead(Q, f))
		printf("输出队头元素的值：%d\n", f);
	printf("输出队列元素的个数：%d\n", QueueLength(Q));
	printf("将Q清为空队列！\n");
	CLearQueue(Q);
	printf("输出队列元素的个数：%d\n", QueueLength(Q));
	printf("判断队列是否为空！\n");
	printf("QueueEmpty(Q)=%d\n", QueueEmpty(Q));
	system("pause");
	
}