73.fseek与宽字符读取文件

• fseek

   //文件路径
       char path[] = "1.txt";
  
       //FILE *pf = fopen(path, "a+");//尾部添加,文件指针在尾部
       //FILE *pf = fopen(path, "w+");//文件指针在头部，清空内容
       FILE *pf = fopen(path, "r+");//文件指针在头部，不清空内容
       fseek(pf, , SEEK_END);
       fputs("", pf);
       fflush(pf);//刷新文件
  
       //插入
       int length = ;
       for (int i = ; i < ;i++)
       {
           fseek(pf, --i-, SEEK_END);
           int ch = fgetc(pf);
   //#define SEEK_CUR    1 当前
   //#define SEEK_END    2 结束
   //#define SEEK_SET    0  开头
  
           fseek(pf, -i-, SEEK_END);
           fputc(ch,pf);
           fflush(pf);//刷新文件
       }
       fseek(pf, -, SEEK_END);//a+ 文件指针移动无效
                                //r+，文件覆盖
       fputs("abcdefg", pf);
       fflush(pf);//刷新文件
  
       fclose(pf);

• 以"rb+"的形式打开文件指针在头部,不清空内容

       char path[] = "1.txt";
       FILE *pf = fopen(path, "rb+");//文件指针在头部，不清空内容
  
       fseek(pf, -, SEEK_END);//a+ 文件指针移动无效
       fputc('', pf);
       fputs("", pf);
  
       rewind(pf);
  
       char ch;
       while ((ch=fgetc(pf))!=EOF)
       {
           putchar(ch);
       }
  
       fclose(pf);

• 宽字符读取文件

   //设定中文
       setlocale(LC_ALL, "zh-CN");
       wchar_t path[] = L"Z:\\I\\百度内部员工联系方式.txt";
       //文件指针在头部，不清空内容
       FILE *pf = _wfopen(path, L"r");
  
       if (pf==NULL)
       {
           printf("error");
       }
       wchar_t wstr[] = {  };
       wchar_t *p = fgetws(wstr, , pf);
       wprintf(L"-%s-\n", wstr);
       p = fgetws(wstr, , pf);
       while (p!=NULL)
       {
           //输出
           wprintf(L"-%s-\n", wstr);
           p = fgetws(wstr, , pf);
       }
  
       fclose(pf);

• 常用宽字符文件函数

   //fgetc  fgetwc
   //fputc fputwc
   //fgets fgetws
   //fputs fputws
   //fprintf  fwprintf
   //fscanf fwscanf
  
   //fread ,fwrite

• fgetwc fputwc putwchar用法示例

       setlocale(LC_ALL, "zh-CN");
       FILE *pfr = _wfopen(L"QQ-腾讯通讯录.txt", L"rb");
       FILE *pfw = _wfopen(L"QQc.txt", L"wb");
       while (!feof(pfr))
       {
           wchar_t ch = fgetwc(pfr);//获取宽字符
           fputwc(ch, pfw);
           putwchar(ch);//显示宽字符
  
       }
       fclose(pfr);
       fclose(pfw);

• fgetws fputws wprintf用法示例

          setlocale(LC_ALL, "zh-CN");
       FILE *pfr = _wfopen(L"QQ-腾讯通讯录.txt", L"rb");
       FILE *pfw = _wfopen(L"QQ.txt", L"wb");
       while (!feof(pfr))
       {
           wchar_t wstr[] = {  };
           fgetws(wstr, , pfr);
           wprintf(L"%ls",wstr);
           fputws(wstr, pfw);//宽字符写入
  
       }
       fclose(pfr);
       fclose(pfw);

• fwscanf fwprintf用法示例

           setlocale(LC_ALL, "zh-CN");
       wchar_t wstr[] = {  };
       fwscanf(stdin, L"%s", wstr);
       fwprintf(stdout, L"%s%d%s", L"你好", ,wstr);