0729作业+梳理

一、作业

1.写一个日志文件，将程序启动后的每一秒时间写入到文件中

代码：

#include<myhead.h>
#include<time.h>
//判断原本文件中的行数
int len_txt(FILE *fp)
{
   char buf=0;
   int count =1;
   while(1)
   {
       buf=fgetc(fp);
       if(buf==EOF)
       {
           break;
       }
       if(buf=='\n')
       {
           count++;
       }
   }
   return count;
}
int main(int argc, const char *argv[])
{
   //设定时间变量
   time_t new_time;
   time_t old_time ;
   struct tm *systime;
   //打开一个存储日志信息的文件
   FILE *fp = NULL;
   if((fp=fopen("./time.txt","a+"))==NULL)
   {
       perror("fopen error");
       return -1;
   }
   char buf[128] = "";//存放转变后的字符串的字符数组
   int len=0;
   len = len_txt(fp);
   while(1)
   {
       new_time = time(NULL);
       systime = localtime(&new_time);
       if(new_time!=old_time)
       {
           old_time = new_time;
           sprintf(buf,"%d、%4d-%2d-%2d %2d:%2d:%2d\n",\
                   ++len,\
                   systime->tm_year+1900,\
                   systime->tm_mon+1,\
                   systime->tm_mday,\
                   systime->tm_hour,\
                   systime->tm_min,\
                   systime->tm_sec);
           fwrite(buf,sizeof(buf),1,fp);
           fflush(fp);
       }
   }
   fclose(fp);

return 0;
}

运行：

2.使用fread和fwrite完成图像的读写操作

代码：

#include<myhead.h>
#define MAX 32
int main(int argc, const char *argv[])
{
   if(argc != 3)
   {
       printf("输入文件错误\n");
       return -1;
   }
   FILE *fp1 = fopen(argv[1],"r");
   if(NULL == fp1)
   {
       perror("fopen argv[1] error");
       return -1;
   }
   FILE *fp2 = fopen(argv[2],"w");
   if(NULL == fp2)
   {
       perror("fopen argv[2] error");
       return -1;
   }
   char buf[MAX] = "";
   int res=0;
   while((res = fread(buf,1,MAX,fp1))!=0)
   {
       fwrite(&buf,1,res,fp2);
   }

   fclose(fp1);
   fclose(fp2);
   return 0;
}

运行：

3.实现bmp图像的读写操作

代码：

#include<myhead.h>
int main(int argc, const char *argv[])
{
   //定义文件指针
   FILE *fp =NULL;
   if((fp = fopen("./gg.bmp","r+"))==NULL)
   {
       perror("fopen error");
       return -1;
   }
   //获取文件大小
   int img_size = 0;
   fseek(fp,2,SEEK_SET);
   fread(&img_size,sizeof(img_size),1,fp);
   printf("size = %d\n",img_size);//图像大小

   //从头向后偏移54字节后就是图像数据
   fseek(fp,54,SEEK_SET);
   unsigned char color[3] = {255,0,255};//正红
   for(int i=0;i<960/2;i++)
   {
       for(int j=0;j<1280;j++)
       {
           fwrite(color,sizeof(color),1,fp);
       }
   }
   return 0;
}