8.2作业

打印时钟在终端上，若终端输入quit，结束时钟

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<head.h>
int main(int argc, const char *argv[])
{
	int fd=open("./1.txt",O_RDWR|O_CREAT|O_TRUNC,0777);
	if(fd<0)
	{
		ERR_MSG("open");
		return -1;
	}
	pid_t cpid=fork();
	if(0==cpid)
	{
		while(1)
		{
			time_t t=time(NULL);
			struct tm*lt=localtime(&t);
			printf("%4d-%02d-%02d %02d:%02d:%02d\r",lt->tm_year+1900,\
					lt->tm_mon+1,lt->tm_mday,lt->tm_hour,\
					lt->tm_min,lt->tm_sec);
			fflush(stdout);
			sleep(1);
			lseek(fd,0,SEEK_SET);
			char ss[10]="";
		int q=read(fd,ss,sizeof(ss));
		if(strcmp(ss,"quit")==0)
			exit(0);
		}
	}
	else if(cpid>0)
	{
		char buf[10]="";
		scanf("%s",buf);
		write(fd,buf,sizeof(buf));
			fflush(stdout);
		wait(NULL);
			}
	else
	{
		ERR_MSG("fork");
		return -1;
	}
	close(fd);
	return 0;
}