• fseek

   1 //文件路徑
   2     char path[150] = "1.txt";
   3 
   4 
   5     //FILE *pf = fopen(path, "a+");//尾部添加,文件指針在尾部
   6     //FILE *pf = fopen(path, "w+");//文件指針在頭部，清空內容
   7     FILE *pf = fopen(path, "r+");//文件指針在頭部，不清空內容
   8     fseek(pf, 0, SEEK_END);
   9     fputs("0000000", pf);
  10     fflush(pf);//刷新文件
  11 
  12 
  13     //插入
  14     int
   
   length = 10;
  15     for (int i = 0; i < 10;i++)
  16     {
  17         fseek(pf, -7-i-1, SEEK_END);
  18         int ch = fgetc(pf);
  19 //#define SEEK_CUR    1 當前
  20 //#define SEEK_END    2 結束
  21 //#define SEEK_SET    0  開頭
  22 
  23         fseek(pf, -i-1, SEEK_END);
  24         fputc(ch,pf);
  25         fflush(pf);//
   
  刷新文件
  26     }
  27     fseek(pf, -17, SEEK_END);//a+ 文件指針移動無效
  28                              //r+，文件覆蓋
  29     fputs("abcdefg", pf);
  30     fflush(pf);//刷新文件
  31 
  32     fclose(pf);

• 以"rb+"的形式打開文件指針在頭部,不清空內容

   1     char path[150] = "1.txt";
   2     FILE *pf = fopen(path, "rb+");//文件指針在頭部，不清空內容
   3 
   4     fseek(pf, -20
   
  , SEEK_END);//a+ 文件指針移動無效
   5     fputc(‘8‘, pf);
   6     fputs("123545", pf);
   7 
   8     rewind(pf);
   9 
  10     char ch;
  11     while ((ch=fgetc(pf))!=EOF)
  12     {
  13         putchar(ch);
  14     }
  15 
  16     fclose(pf);

• 寬字符讀取文件

   1 //設定中文
   2     setlocale(LC_ALL, "zh-CN");
   3     wchar_t path[150] = L"Z:\\I\\百度內部員工聯系方式.txt";
   4     //文件指針在頭部，不清空內容
   5     FILE *pf = _wfopen(path, L"r");
   6     
   7     if (pf==NULL)
   8     {
   9         printf("error");
  10     }
  11     wchar_t wstr[1128] = { 0 };
  12     wchar_t *p = fgetws(wstr, 1128, pf);
  13     wprintf(L"-%s-\n", wstr);
  14     p = fgetws(wstr, 1128, pf);
  15     while (p!=NULL)
  16     {
  17         //輸出
  18         wprintf(L"-%s-\n", wstr);
  19         p = fgetws(wstr, 1128, pf);
  20     }
  21 
  22     fclose(pf);

73.fseek與寬字符讀取文件