代码练习

使用fread和fwrite完成两个文件的拷贝

#include<myhead.h>int main(int argc, const char *argv[])
{FILE *fp = NULL;//重新以只读的形式打开文件if((fp = fopen("./OIP-C.bmp", "r")) == NULL){perror("fopen error");return -1;}FILE *fp1=NULL;if((fp1=fopen("./text.bmp","w"))==NULL){perror("fopen error");return -1;}char head[54]="";unsigned char color[3];fread(head, sizeof(head), 1, fp); //读取头fwrite(head, sizeof(head), 1, fp1);//写入头while(fread(color,sizeof(char),3,fp)==3)//读取像素点{fwrite(color,sizeof(char),3,fp1);//写入像素点}//关闭文件fclose(fp);fclose(fp1);return 0;
}

效果图

使用read、write完成两个文件的拷贝

#include<myhead.h>int main(int argc, const char *argv[])
{//定义文件描述符变量int fd = -1;if((fd = open("./text.bmp", O_RDONLY)) == -1){perror("open error");return -1;}int fd1=-1;if((fd1=open("./work3.bmp",O_WRONLY))==-1){perror("open error");return -1;}char head[54]="";unsigned char color[3]="";lseek(fd, 0, SEEK_SET);        //将光标移到开头read(fd,head, 54);//读取头write(fd1,head,54);//写入头//将光标偏移到矩阵部分lseek(fd, 54, SEEK_SET);while(read(fd,color,sizeof(color))==3)//读取像素{write(fd1,color,sizeof(color));//写入像素}//关闭文件close(fd);close(fd1);return 0;
}

 效果图

将时间在文件中跑起来

#include <myhead.h>
//将时间在文件中跑起来
int main(int argc, const char *argv[])
{//打开时间文件FILE *fp=NULL;if((fp=fopen("./time.txt","a+"))==NULL){perror("fopen error");return -1;}//循环计算已有行号int line=1;while(1){char c=fgetc(fp);if(c=='\n')line++;if(c==EOF)break;}//判断新旧时间char time_buf[128]="";struct tm *t;time_t Old_Time,sysTime;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",time_buf);fputs(time_buf,fp);line++;fflush(fp);}}fclose(fp);return 0;
}

效果图

思维导图