#include "stdafx.h" #include <windows.h> void main(int argc, char* argv[]) {       HANDLE hDevice = CreateFile("C://S.txt",             GENERIC_READ|GENERIC_WRITE,             0,             NULL,             OPEN_EXISTING,             FILE_ATTRIBUTE_NORMAL,             NULL);       if (hDevice == INVALID_HANDLE_VALUE)       {              printf("Failed to obtain file with %d error code !/n",GetLastError());              return;       }       DWORD dwSize = GetFileSize(hDevice,NULL);       printf("%d /n",dwSize);       char chBuffer[10] = "5469";       DWORD dwWriteSize = 0;       BOOL bRet = WriteFile(hDevice,chBuffer,4,&dwWriteSize,NULL);       if(bRet)       {              printf("write file success /n");       }       FlushFileBuffers(hDevice);   //将缓冲区数据写入磁盘       LONG IDistance = 0;       DWORD dwPtr = SetFilePointer(hDevice,IDistance,NULL,FILE_BEGIN);  //调整文件指针到文件开头       DWORD dwReadSize = 0;       bRet = ReadFile(hDevice,chBuffer,10,&dwReadSize,NULL);       if (bRet)       {               printf("chbuffer is %s /n",chBuffer);       }       CloseHandle(hDevice);       return ; }

      char datain[101];       FILE *fp_sys;       fp_sys = fopen("要打开的文件名", "rb"); //第二个参数为打开方法，r代表读，b代表二进制方式       if(fp_sys == NULL) {              AfxMessageBox("无法打开充值卡文件");