#include <iostream>
#include <vector>
#include <string>

int main()
{
    std::vector<int> vec{1,4,2,6,9,10,17,13,15};
    auto last_it = vec.crbegin();
    
    for(auto it = vec.cbegin(); it != vec.cend(); ++it, ++last_it)
    {
        int first_last = *it + *last_it;
        std::cout << "Add First and Last Digit : " << first_last << std::endl;
    }

    return 0;
}