add.cpp

#include <iostream>
#include <vector>
using namespace std;

    int adder(vector<int> &myElements, int &sum)
    {
        if (myElements.size() == 0)
        {
            cout << "sum " << sum << endl;
            return sum;
        }
        sum += myElements.back();
        myElements.pop_back();
        adder(myElements, sum);
    }
// int adder(vector<int> elems)
// {
//     if (elems.size() == 1)
//         return elems[0];
//     else
//     {
//         int elem = elems.back();
//         elems.pop_back();
//         return elem + adder(elems);
//     }
// }
int main()
{
    int sum = 0;
    vector<int> nums1 = {1, 2, 3, 4};
    vector<int> nums2 = {100, 200, 300, 400};
    vector<int> nums3 = {1000, 2000, 3000, 4000};
    cout << "Sum" << adder(nums1, sum) << endl;
    cout << "Sum" << adder(nums2, sum) << endl;
    cout << "Sum" << adder(nums3, sum) << endl;
    // add(nums2, 0);
    // add(nums3, 0);
    return 0;
}