String& String::operator=(const String& right)
{
   if (this != &right)
   {
      delete[] buffer; // Get rid of old buffer
      len = right.length();
      buffer = new char[len + 1];
      for (int i = 0; i < len; i++)
         buffer[i] = right[i];
      buffer[len] = '\0';
   }
   return *this;
}