IO进程线程Day1

1> 使用fgets统计一个文件的行号

#include
#include
#include
int main(int argc, const char *argv[])
{
	//定义文件指针
	FILE *fp=NULL;
	//以只读的形式打开文件
	fp=fopen("./text.txt","r");
	if(fp==NULL)
	{
		perror("fopen,error");
		return -1;
	}
	//定义一个变量用于从文件中读取数据
	char buf=0;
	int count=0;
	while(buf!=EOF)
	{
		buf=fgetc(fp);
		if(buf=='\n')//每当读取到\n，count++
			count++;
	}
	printf("count=%d\n",count);
	//关闭文件
	fclose(fp);
    return 0;
}

2> 使用fgets、fputs完成两个文件的拷贝

#include 
#include 
#include 
int main(int argc, const char *argv[])
{
	FILE *srcfp=NULL,*dstfp=NULL;

	if(argc!=3)//判断外部传参的个数
	{
		printf("input file error\n");
		printf("usage: ./a.out srcfile dstfile\n");
		return 0;
	}

	if((srcfp=fopen(argv[1],"r"))==NULL)//以只读的形式打开源文件
	{
		perror("srcfile open error");
		return -1;
	}
	if((dstfp=fopen(argv[2],"w"))==NULL)//以只写的形式打开目标文件
	{
		perror("dstfile open error");
		return -1;
	}

	char buf[128]="";//定义一个字符搬运工
	while(fgets(buf,sizeof(buf),srcfp)!=NULL)
		fputs(buf,dstfp);
	
	printf("拷贝成功\n");
	fclose(srcfp);
	fclose(dstfp);

	return 0;
}

3> 向文件中输出当前的系统时间

#include 
#include 
#include 
#include 
#include 
 
int main(int argc, const char *argv[])
{
	FILE *file;
	int count=0;
	file=fopen("time.txt","a");
	if(file==NULL)
	{
		perror("未找到文件");
		return -1;
	}
	FILE *lineNumberFile=fopen("time.txt","r");
	int lineNumber=0;
	char line[1024]="";
	while(fgets(line,sizeof(line),lineNumberFile)!=NULL)
	{
		lineNumber++;
	}
	fclose(lineNumberFile);
	printf("lineNumber=%d\n",lineNumber);
	while(1)
	{
		count++;
		time_t sys_time=0;
		time(&sys_time);
		struct tm *t=localtime(&sys_time);
		char timeString[100]="";
		sprintf(timeString,"%d: %4d-%2d-%2d %2d:%2d:%2d\n",lineNumber+count,t->tm_year+1900,\
				t->tm_mon+1,t->tm_mday,t->tm_hour,t->tm_min,t->tm_sec);
		printf("%s\n",timeString);
		
		fputs(timeString,file);
		fflush(file);
 
		sleep(1);
	}
 
 
	fclose(file);
 
	return 0;
}