离散事件模型

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

#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0

typedef int Status;
typedef struct Event {   //事件类型
	int OccurTime;  //事件发生时刻
	int NType;      //事件类型，0表示到达事件，1至4表示四个窗口的离开事件
	struct Event *next;
}Event, ElemType;

typedef struct { //单向链表结构
	ElemType *head;//头指针
	ElemType *tail;//尾指针
	int len;    //长度
}LinkList;

typedef LinkList EventList; //事件链表

typedef struct QElemType { //队列元素
	int ArriveTime;//到达时间
	int Duration;//办理业务所需时间
	struct QElemType *next;
}QElemType;

typedef struct {//队列结构
	QElemType *head;//头指针
	QElemType *tail;//尾指针
}LinkQueue;

Event NewEvent(int occurT, int nType);
//根据OccurTime和NType值，创建新事件
Status InitList(LinkList *L);
//初始化事件链表
Status OrderInsert(LinkList *L, Event e);
//将事件e按发生时间顺序插入有序链表L中
Status ListEmpty(LinkList *L);
//判断链表L是否为空，为空返回TRUE，否则返回FALSE
Status DelFirst(LinkList *L, ElemType *e);
//链表L不为空，删除其首结点，用e返回，并返回OK；否则返回ERROR
Status ListTraverse(LinkList *L);
//遍历链表
Status InitQueue(LinkQueue *Q);
//初始化队列Q
Status EmptyQueue(LinkQueue *Q);
//若队列Q为空，返回TRUE，否则返回FALSE
Status DelQueue(LinkQueue *Q, QElemType *e);
//若队列Q不为空，首结点出队，用e返回，并返回OK；否则返回ERROR
Status EnQueue(LinkQueue *Q, QElemType e);
//结点e入队Q
int QueueLength(LinkQueue Q);
//返回队列Q的长度，即元素个数
Status GetHead(LinkQueue *Q, QElemType *e);
//若队列Q不为空，用e返回其首结点，并返回OK,否则返回ERROR
Status QueueTraverse(LinkQueue *Q);
//遍历队列Q

//------------------//
int Min(int a[], int n);
//返回长度为n的数组a第一个最小值的下标，从1开始
int ShortestQueue();
//获取最短队列的编号
void OpenForDay();
//初始化操作
void CustomerArrived();
//顾客达到事件
void CustomerDepature();
//顾客离开事件
void Bank_Simulation();
//银行排队模拟
void PrintEventList();
//输出事件队列
void PrintQueue();
//打印当前队列
//----全局变量-----//
EventList ev;
Event en;
LinkQueue q[5];
QElemType customer;
int TotalTime, CustomerNum;
int CloseTime = 50;//关闭时间，即营业时间长度

				   //--------------main()------------------//
int main()
{
	Bank_Simulation();
	return 0;
}


//--------------模拟排队----------------//
void OpenForDay() {
	//初始化操作
	int i;
	TotalTime = 0;    CustomerNum = 0;
	InitList(&ev);//初始化事件链表
	en.OccurTime = 0;
	en.NType = 0;
	OrderInsert(&ev, en);
	for (i = 1; i <= 4; i++)
		InitQueue(&q[i]);//初始化四个窗口队列
}//OpenForDay

void CustomerArrived() {
	//顾客达到事件
	int durtime, intertime, i, t;
	QElemType e;
	++CustomerNum;
	intertime = rand() % 5 + 1;//间隔时间在5分钟内
	durtime = rand() % 30 + 1;//办理业务时间在30分钟内
	t = en.OccurTime + intertime;
	if (t<CloseTime) {//银行尚未关门
		printf("A new customer will arrive at:%d\n", en.OccurTime);//下一位顾客达到时间
		OrderInsert(&ev, NewEvent(t, 0));
		i = ShortestQueue();//最短队列
		e.ArriveTime = en.OccurTime;
		e.Duration = durtime;
		EnQueue(&q[i], e);
		if (QueueLength(q[i]) == 1)
			OrderInsert(&ev, NewEvent(en.OccurTime + durtime, i));
	}
}

void CustomerDepature() {
	//顾客离开事件
	int i = en.NType;
	DelQueue(&q[i], &customer);
	printf("A customer leaves at:%d\n", en.OccurTime);//输出顾客离开时间
	TotalTime += en.OccurTime - customer.ArriveTime;
	if (!EmptyQueue(&q[i])) {
		GetHead(&q[i], &customer);
		OrderInsert(&ev, NewEvent(en.OccurTime + customer.Duration, i));
	}
}

void Bank_Simulation() {
	//银行排队模拟
	OpenForDay();
	srand((unsigned)time(NULL));
	while (!ListEmpty(&ev)) {
		DelFirst(&ev, &en);  //事件驱动
		if (en.NType == 0)
			CustomerArrived();
		else
			CustomerDepature();
		//PrintEventList();
		PrintQueue();
	}
	printf("\nTotal time is: %d min,average time is: %g min.\n", TotalTime, (float)TotalTime / CustomerNum);
}

void PrintQueue() {
	//打印当前队列
	int i;
	for (i = 1; i <= 4; i++) {
		printf("Queue %d have %d customer(s):", i, QueueLength(q[i]));
		QueueTraverse(&q[i]);
	}
	printf("\n");
}

void PrintEventList() {
	//输出事件队列
	printf("Current Eventlist is：\n");
	ListTraverse(&ev);
}
int Min(int a[], int n) {
	//返回长度为n的数组a第一个最小值的下标，从0开始
	int i, tmp, ind = 0;
	tmp = a[0];
	for (i = 1; i<n; i++) {
		if (a[i]<tmp) {
			tmp = a[i];
			ind = i;
		}
	}
	return ind;
}

int ShortestQueue() {
	//获取最短队列的编号
	int i, a[4];
	for (i = 1; i <= 4; i++) {
		a[i - 1] = QueueLength(q[i]);
		//printf("队%d的长度为%d\n",i,QueueLength(q[i]));
	}
	return Min(a, 4) + 1;//队列从1开始编号
}

//-----------队和链表操作--------------//
Event NewEvent(int occurT, int nType) {
	//根据OccurTime和NType值，创建新事件
	Event e;
	e.OccurTime = occurT;
	e.NType = nType;
	return e;
}

Status InitList(LinkList *L) {
	//初始化事件链表
	L->head = L->tail = (ElemType *)malloc(sizeof(ElemType));
	if (!L->head) {
		printf("Apply for memory error.LinkList initialize failed.\n");
		exit(0);
	}
	L->head->next = NULL;
	return OK;
}

Status OrderInsert(LinkList *L, Event e) {
	//将事件e按发生时间顺序插入有序链表L中
	ElemType *p, *q, *newptr;
	newptr = (ElemType *)malloc(sizeof(ElemType));
	if (!newptr) {
		printf("Apply for memory error，new node can‘t insert intot the Eventlist.\n");
		exit(0);
	}
	*newptr = e;
	if (TRUE == ListEmpty(L)) {//链表为空
		L->head->next = newptr;
		L->tail = newptr;
		L->tail->next = NULL;
		return OK;
	}
	q = L->head;
	p = L->head->next;
	while (p) {//遍历整个链表
		if (p->OccurTime >= newptr->OccurTime)
			break;
		q = p;
		p = p->next;
	}
	q->next = newptr;
	newptr->next = p;
	if (!p)//插入位置为链表尾部
		L->tail = newptr;
	return OK;
}

Status ListEmpty(LinkList *L) {
	//判断链表L是否为空，为空返回TRUE，否则返回FALSE
	if ((L->head == L->tail) && (L->head != NULL))
		return TRUE;
	else
		return FALSE;
}

Status DelFirst(LinkList *L, ElemType *e) {
	//链表L不为空，删除其首结点，用e返回，并返回OK；否则返回ERROR
	ElemType *p = L->head->next;
	if (!p)
		return ERROR;
	L->head->next = p->next;
	*e = *p;
	free(p);
	if (L->head->next == NULL)
		L->tail = L->head;
	return OK;
}

Status ListTraverse(LinkList *L) {
	//遍历链表
	Event *p = L->head->next;
	if (!p) {
		printf("List is empty.\n");
		return ERROR;
	}
	while (p != NULL) {
		printf("OccurTime:%d,Event Type:%d\n", p->OccurTime, p->NType);
		p = p->next;
	}
	printf("\n");
	return OK;
}

Status InitQueue(LinkQueue *Q) {
	//初始化队列Q
	Q->head = Q->tail = (QElemType *)malloc(sizeof(QElemType));
	if (!Q->head) {
		printf("Apply for memory error.LinkQueue initialize failed.\n");
		exit(0);
	}
	Q->head->next = NULL;
	return OK;
}

Status EmptyQueue(LinkQueue *Q) {
	//若队列Q为空，返回TRUE，否则返回FALSE
	if (Q->head == Q->tail&&Q->head != NULL)
		return TRUE;
	else
		return FALSE;
}

Status DelQueue(LinkQueue *Q, QElemType *e) {
	//若队列Q不为空，首结点出队，用e返回，并返回OK；否则返回ERROR
	QElemType *p = Q->head->next;
	if (!p)
		return ERROR;
	*e = *p;
	Q->head->next = p->next;//修正队首指针
	free(p);
	if (!Q->head->next)//队空
		Q->tail = Q->head;
	return OK;
}

Status EnQueue(LinkQueue *Q, QElemType e) {
	//结点e入队Q
	QElemType *p = (QElemType *)malloc(sizeof(QElemType));
	if (!p) {
		printf("Apply for memory error,new element can‘t enqueue.\n");
		exit(0);
	}
	*p = e;
	p->next = NULL;
	Q->tail->next = p;//插入队尾
	Q->tail = p;//修改队尾指针
	return OK;
}

int QueueLength(LinkQueue Q) {
	//返回队列Q的长度，即元素个数
	int count = 0;
	QElemType *p = Q.head->next;
	while (p) {
		p = p->next;
		count++;
	}
	return count;
}

Status GetHead(LinkQueue *Q, QElemType *e) {
	//若队列Q不为空，用e返回其首结点，并返回OK,否则返回ERROR
	if (EmptyQueue(Q))
		return ERROR;
	*e = *(Q->head->next);
	return OK;
}

Status QueueTraverse(LinkQueue *Q) {
	//遍历队列Q
	QElemType *p = Q->head->next;
	if (!p) {
		printf("--Is empty.\n");
		return ERROR;
	}
	while (p) {
		printf("(%d,%d) ", p->ArriveTime, p->Duration);
		p = p->next;
	}
	printf("\n");
	return OK;
}