feof函数返回值始终是零？？？？？？？？？？？？？？？？？？？？？？？

                    while (!feof(openfile))
                    {
                        str = fgetc(openfile);
                        str = str + '\10';
                        fputc(str, openfile);
                        printf("%c", str);
                        if (ferror(openfile))
                        {
                            perror("Read error");
                            break;
                        }
                        a = feof(openfile);
                        printf("%d",a );
                    }

http://www.cnblogs.com/ayanmw/archive/2012/09/12/2682016.html

 #include <stdio.h>
#include <stdlib.h>

void main( void )
{
   int  count, total = 0;
   char buffer[100];
   FILE *stream;

   if( (stream = fopen( "feof.c", "r" )) == NULL )
      exit( 1 );

   /* Cycle until end of file reached: */
   while( !feof( stream ) )
   {
      /* Attempt to read in 10 bytes: */
      count = fread( buffer, sizeof( char ), 100, stream );
      if( ferror( stream ) )      {
         printf( "Read error" );
         break;
      }

      /* Total up actual bytes read */
      total += count;
   }
   printf( "Number of bytes read = %d\n", total );
   fclose( stream );
}