Readfile() And Createfile(). How Do I Use Them?

//  Creates the new file to write to for the upper-case version.
hTempFile = CreateFile((LPTSTR) szTempFileName, // file name
                       GENERIC_WRITE,        // open for write
                       0,                    // do not share
                       NULL,                 // default security
                       CREATE_ALWAYS,        // overwrite existing
                       FILE_ATTRIBUTE_NORMAL,// normal file
                       NULL);                // no template
if (hTempFile == INVALID_HANDLE_VALUE)
{
    PrintError(TEXT("Second CreateFile failed"));
    if (!CloseHandle(hFile))
    {
        PrintError(TEXT("CloseHandle(hFile) failed"));
        return (7);
    }
    return (4);
}

//  Reads BUFSIZE blocks to the buffer and converts all characters in
//  the buffer to upper case, then writes the buffer to the temporary
//  file.
do
{
    if (ReadFile(hFile, chBuffer, BUFSIZE, &dwBytesRead, NULL))
    {
        //  Replaces lower case letters with upper case
        //  in place (using the same buffer). The return
        //  value is the number of replacements performed,
        //  which we aren't interested in for this demo.
        CharUpperBuffA(chBuffer, dwBytesRead);

        fSuccess = WriteFile(hTempFile,
                             chBuffer,
                             dwBytesRead,
                             &dwBytesWritten,
                             NULL);
        if (!fSuccess)
        {
            PrintError(TEXT("WriteFile failed"));
            return (5);
        }
    }
    else
    {
        PrintError(TEXT("ReadFile failed"));
        return (6);
    }
//  Continues until the whole file is processed.
} while (dwBytesRead == BUFSIZE);

//  The handles to the files are no longer needed, so
//  they are closed prior to moving the new file.
if (!CloseHandle(hFile))
{
   PrintError(TEXT("CloseHandle(hFile) failed"));
   return (7);
}

Quote:

And to further improve my program how can i create variables in a loop which i can use later in the program?