1. on windows: don't hang when there's no console, that is, _getch() returns -1. 
2. on windows: _getch() returns an int, not char.
   to distinguish between (char)255 and (int)-1
3. everywhere. isspace(pos[-1]) == ' ' never worked,
   isspace() returns a boolean, not a char. the never-worked loop was
   removed to preserve the existing behavior.