cpp-useful-iterators/test/ranges.h

//
//  ranges.h
//  iterator
//
//  Created by Sam Jaffe on 4/1/23.
//  Copyright © 2023 Sam Jaffe. All rights reserved.
//

#pragma once

namespace ranges {
template <typename It, typename S, typename F>
auto for_each(It it, S end, F consumer) {
  for (; it != end; ++it) {
    std::invoke(consumer, *it);
  }
  return std::make_pair(it, consumer);
}

template <typename It, typename S> auto distance(It it, S end) {
  typename std::iterator_traits<It>::difference_type diff{0};
  for_each(it, end, [&diff](auto const &) { ++diff; });
  return diff;
}

template <template <typename...> class C, typename It, typename S>
auto to(It it, S end) {
  decltype(C(it, it)) rval;
  for_each(it, end,
           [&rval](auto const & elem) { rval.insert(rval.end(), elem); });
  return rval;
}

template <typename C, typename It, typename S> auto to(It it, S end) {
  C rval;
  for_each(it, end,
           [&rval](auto const & elem) { rval.insert(rval.end(), elem); });
  return rval;
}
}