traversals_3_terrible_design.cpp

struct batch_options
{
   bool m_with_minimum;
   bool m_with_average;
   bool m_with_variations;
   double m_limit;
   std::function<bool (stock_update const&)> m_filter;
};

struct batch_result
{
   double m_minimum;
   double m_average;
   int m_variation_count;
};

batch_result terrible_design(std::vector<std::string> const& source, batch_options const& options)
{
   batch_result result;
   result.m_minimum = std::numeric_limits<double>::max();
   result.m_average = 0.0;
   result.m_variation_count = 0;
   
   int count = 0;
   double init_value = 0.0;
   for (auto& msg: source)
   {
      stock_update s = parse_message(msg);
      if (!options.m_filter(s))
         continue;
      
      if (count == 0)
         init_value = s.m_value;
      ++count;
      
      if (options.m_with_minimum)
         result.m_minimum = std::min(result.m_minimum, s.m_value);
      if (options.m_with_average)
         result.m_average += s.m_value;
      if (options.m_with_variations)
         if (abs(s.m_value - init_value) > options.m_limit)
            ++result.m_variation_count;
   }
   
   if (count)
      result.m_average /= count;
   return result;
}