in = fopen("input.txt", "r", "native");
out = fopen("output.txt", "w","native");
if (in == -1)
  disp("Error opening input.txt for reading.");
else
if (out == -1)
  disp("Error opening output.txt for writing.");
else
while (1)
  [val,count]=fread(in,1,"uchar",0,"native");
  if (count > 0)
    count=fwrite(out,val,"uchar",0,"native");
    if (count == 0)
      disp("Error writing to output.txt.");
    end
  else
    break;
  end
endwhile
end
end
if (in != -1)
  fclose(in);
end
if (out != -1)
  fclose(out);
end