//********************************************************
// The following code example is taken from the book
//  C++20 - The Complete Guide
//  by Nicolai M. Josuttis (www.josuttis.com)
//  http://www.cppstd20.com
//
// The code is licensed under a
//  Creative Commons Attribution 4.0 International License
//  http://creativecommons.org/licenses/by/4.0/
//********************************************************


#include <vector>
#include <ranges>
#include <algorithm>
#include <numeric>

template<std::ranges::input_range T>
constexpr auto modifiedAvg(const T& rg)
{
  using elemType = std::ranges::range_value_t<T>;

  // initialize compile-time vector with passed elements:
  std::vector<elemType> v{std::ranges::begin(rg),
                          std::ranges::end(rg)};
  // perform several modifications:
  v.push_back(elemType{});
  std::ranges::sort(v);
  auto newEnd = std::unique(v.begin(), v.end());
  //...

  // return average of modified vector:
  auto sum = std::accumulate(v.begin(), newEnd,
                             elemType{});
  return sum / static_cast<double>(v.size());
}