#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>

int main() {
  std::vector<int> a{1,2,3,4};
  std::vector<int> b{5,6,7,8};
  // result vector
  std::vector<double> c(a.size(), 0);

  // double
  std::for_each(a.begin(), a.end(), [](int &n){ n*=2;});
  
  std::cout << "Double:" << std::endl;
  for (auto const &i: a){ std::cout<<i<<" ";}
  std::cout << std::endl;

  // Reset a
  a = {1,2,3,4};
  
  // inverse
  std::transform(a.begin(), a.end(),
                 c.begin(),
                 [](int i){return 1.0/i;});

  std::cout << "Multiplicative inverse:" << std::endl;
  for (auto const &i: c){ std::cout << i << " ";}
  std::cout << std::endl;

  // reziprocal sum
  std::transform(a.begin(), a.end(),
                 b.begin(), c.begin(),
                 [](int i, int j){return 1.0/(1.0/i + 1.0/j);});
  std::cout << "Reziprocal sum:" << std::endl;
  for (auto const &i: c){ std::cout << i << " ";}
  std::cout << std::endl;

  // Folds
  int sum = std::accumulate(a.begin(), a.end(), 0);
  int diff = std::accumulate(a.begin(), a.end(), 15, std::minus<int>());
  int mult = std::accumulate(a.begin(), a.end(), 1,
                             [](int a, int b)->int { return a * b; });
  std::cout << "Sum: " << sum
            << "\nDiff from 15: " << diff
            << "\nProd: " << mult
            << std::endl;
  
  return 0;
}