IO进程线程day3作业

1、使用 fread 和 fwrite 完成文件拷贝

代码：

#include<myhead.h>
int main(int argc, const char *argv[])
{//判断终端输入if(argc!=3){printf("inputs file error\n");printf("usage:./a.out srcfile destfile\n");return -1;}//定义文件指针，以只读形式打开FILE *srcfp = NULL;if((srcfp=fopen(argv[1],"r"))==NULL){perror("fopen error");return -1;}//定义文件指针，以只写形式打开FILE *destfp=NULL;if((destfp=fopen(argv[2],"w"))==NULL){perror("fopen error");return -1;}//拷贝char buf[128]="";int res = fread(buf,1,sizeof(buf),srcfp);fwrite(buf,1,res,destfp);//关闭文件fclose(srcfp);fclose(destfp);return 0;
}

运行结果：

2、使用read和write完成文件的拷贝

代码：

#include<myhead.h>
int main(int argc, const char *argv[])
{//判断终端输入if(argc!=3){printf("inputs file error\n");printf("usage:./a.out srcfile destfile\n");return -1;}//定义文件描述符变量int fd1 = -1;//只读打开文件if((fd1=open("./test.txt",O_RDONLY))==-1){perror("open error");return -1;}//定义文件描述符变量int fd2 = -1;//只写打开文件if((fd2=open("./aa.txt",O_WRONLY | O_CREAT,0664))==-1){perror("open error");return -1;}//拷贝char buf[128]="";int res=read(fd1,buf,sizeof(buf));write(fd2,buf,res);return 0;
}

运行结果：

3、将时间在文件中跑起来

代码：

#include<myhead.h>
int main(int argc, const char *argv[])
{FILE *fp=NULL;if((fp=fopen("./time.txt","a+"))==NULL){perror("fopen error");return -1;}int line =1;int c=0;while(1){c=getc(fp);if(c=='\n')line++;if(c==EOF)break;}char time_buf[128]="";time_t old_time,systime;struct tm *t;while(1){systime=time(NULL);if(old_time!=systime){old_time=systime;t=localtime(&systime);snprintf(time_buf,sizeof(time_buf),"%d:%2d:%2d:%2d\n",\line,t->tm_hour,t->tm_min,t->tm_sec);printf("%s\n",time_buf);fputs(time_buf,fp);line++;fflush(fp);}}fclose(fp);return 0;
}

运行结果：

4、用fread和fwrite完成图片的拷贝

代码：

#include<myhead.h>
int main(int argc, const char *argv[])
{//只读打开FILE *fp1=NULL;if((fp1=fopen("./picture.bmp","r"))==NULL){perror("fopen error");return -1;}//只写打开FILE *fp2=NULL;if((fp2=fopen("./cp.bmp","w"))==NULL){perror("fopen error");return -1;}//定义元素存储数据char buf;while(1){fread(&buf,1,1,fp1); //从指定文件中读取数据fwrite(&buf,1,1,fp2); //把数据写入指定文件//判断文件是否读取结束if(feof(fp1)||ferror(fp1)){break;}}//关闭文件fclose(fp1);fclose(fp2);return 0;
}