8_4.c

gc:高级程序员考试用书的c程序源文件

# include <stdio.h>
# include <stdlib.h>
typedef struct {               // 顾客信息结构
	int arrive;
	int treat;
}NODE;

typedef struct node {
	NODE data;
	struct node *link;
}LNODE;

LNODE *head,*tail;

NODE curr,temp;

char Fname[120];
FILE *fp;           //指向FILE类型结构体的指针变量

/*函数,链接队列进队函数*/
void len_queue(LNODE **hpt,LNODE **tpt,NODE x)
{
	LNODE *p = (LNODE *)malloc(sizeof(LNODE));
	p->data = x;
	p->link = NULL;
	if (*hpt == NULL) *tpt = *hpt = p;
	else
		*tpt = (*tpt)->link = p;
}

/*函数,链接队列出队函数*/
int lde_queue(LNODE **hpt,LNODE **tpt,NODE *cp)
{
	LNODE *p = *hpt;
	if (*hpt == NULL) return 1 ;               //对空
	*cp = (*hpt)->data;
	*hpt = (*hpt)->link;
	if (*hpt == NULL) *tpt = NULL;
	free(p);
	return 0;
}


void main()
{
	int dwait = 0,         //接待员总等待时间
	clock = 0,
	wait = 0,              //顾客总等待时间
	count = 0,             //顾客总人数
	have = 0,finish;
	printf("Enter file name.");
	printf("输入同目录下wait.txt的完整物理路径\n");
	scanf("%s",Fname);
	if ((fp = fopen(Fname,"r")) == NULL) {            //打开文件
		printf("Can't open file %s",Fname);
		return;
	}
	head = NULL; tail=NULL;
	have = fscanf(fp,"%d%d",&temp.arrive, &temp.treat);   /*正确读入,have为2*/
	do {   /*约定每轮循环,接待一位顾客*/
		if (head == NULL && have == 2) {    /*等待队列为空,但还有顾客*/
			dwait += temp.arrive - clock;   /*累计接待员总等待时间  */
			clock = temp.arrive;            /*时钟推进到暂存顾客的到达时间*/
			len_queue(&head,&tail,temp);    /*暂存变量中的顾客信息进队*/
			have = fscanf(fp,"%d%d",&temp.arrive,&temp.treat); /*fp,文件指针,从磁盘文件上读入*/
		}
		count ++;                      /*累计顾客人数*/
		lde_queue(&head,&tail,&curr);  /*出队一个顾客信息*/
		wait += clock - curr.arrive;      /*累计顾客的总等待时间*/
		finish = clock + curr.treat;       /*设定接待结束时间*/
		while (have == 2 && temp.arrive <= finish) {
			/*下一位顾客的到达时间在当前顾客接待结束之前*/
			len_queue(&head,&tail,temp);       /*暂存变量中的顾客信息进队*/
			have = fscanf(fp,"%d%d",&temp.arrive,&temp.treat);
		}
		clock = finish;          /*时钟推进到当前顾客接待结束时间 */
	} while(have == 2 || head!=NULL);
	printf("结果:接待员等待时间%d\n顾客平均等待时间%f\n",dwait,(double)wait/count);
	printf("模拟总时间:%d,顾客人数:%d,总等待时间:%d\n",clock,count,wait);
}