cpp-example2.cpp

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

int main() {

  std::vector<int> v{1,2,3,4};
  
  std::vector<int> b;
  std::transform(v.begin(), v.end(), std::back_inserter(b), [](int a){return 2 * a;});
  
  auto it = std::remove_if(b.begin(), b.end(), [](int a){return a % 6 != 0;});
  b.erase(it, b.end());

  int res = std::accumulate(b.begin(), b.end(), 0); // by default, accumulate adds all the elements
  
  std::cout << res << "\n";  
  
  return 0;
}