#include?“stdio.h“
#include?“malloc.h“

#define?MAXSIZE?10??????????????????????????/*窗口大小，即隊列大小*/

int?i=0;?????????????????????????????????????/*全局變量，代表當(dāng)前指向確認(rèn)表的位置*/

typedef?struct??????????????????????????????/*發(fā)送窗口每幀的數(shù)據(jù)*/
{
	int?snum;??
	int?timeout;/*非0時代表發(fā)送計時，=6時表明超時*/
}send;

typedef?struct??????????????????/*發(fā)送窗口*/
{
	send?s[MAXSIZE];
	int?front;
	int?rear;
}wsend;

typedef?struct??????????????????/*接收窗口*/
{
	int?r[MAXSIZE];
	int?front;
	int?rear;
}wrece;

void?Init（wsend?*wswrece?*wr）??/*對發(fā)送和接收窗口進(jìn)行初始化*/
{
	ws->front=ws->rear=0;
	wr->front=wr->rear=0;
}

int?SEND（wsend?*wswrece?*wrint?frame）
{
	if（（ws->rear+1）%MAXSIZE==ws->front）return?0;???/*發(fā)送窗口已滿*/
	if（ws->front==ws->rear）????????????????????????/*若窗口為空，則直接進(jìn)入*/
	{
		ws->s[ws->rear].snum=frame;
		ws->s[ws->rear].timeout=1;
		ws->rear=（ws->rear+1）%MAXSIZE;
		wr->r[wr->rear]=frame;
		wr->rear=（wr->rear+1）%MAXSIZE;
		return?1;
	}
	else?????????????????????????????????????????/*若窗口不為空，則判斷是否是可傳送的幀*/?
	{
		if（frame==（ws->s[ws->rear-1].snum）+1）
	{
		ws->s[ws->rear].snum=frame;
		ws->s[ws->rear].timeout=1;
		ws->rear=（ws->rear+1）%MAXSIZE;
		wr->r[wr->rear]=frame;
		wr->rear=（wr->rear+1）%MAXSIZE;
		return?1;
	}
	else?if（frame<（ws->s[ws->rear-1].snum）+1）printf（“該幀已發(fā)送！！\n“）;
	else?if（frame>（ws->s[ws->rear-1].snum）+1）printf（“該幀不可發(fā)送?。n“）;
	}
}

int?RECE（wrece?*wrint?frameint?ack[]）
{
	if（wr->front==wr->rear）?return?0;???????/*接收窗口為空*/
	else????????????????????????????????????/*接收窗口接收幀號，并返回確認(rèn)*/
	{
		if（wr->r[wr->front]==frame）?
		{
			wr->front=（wr->front+1）%MAXSIZE;
			printf（“第%d幀出接收窗口，向發(fā)送窗口返回確認(rèn)。\n“frame）;
			ack[i]=frame;
			i++;
		}
		else???printf（“該幀不是期望收到的幀，舍棄。\n“）;
		return?1;
	}
}

int?ACKNOWLEDGE（wsend?*wsint?ack[]）
{
	int?j;
	if（ws->front==ws->rear）?return?0;????????/*發(fā)送窗口為空*/
	if（ack[0]==ws->s[ws->front].snum）????????/*發(fā)送窗口進(jìn)