sum vector c 2b 2b

1accumulate(a.begin(), a.end(), 0);

1  vector<int> v{1,2,3,4,5,6,7,8,9};
2  int sum = 0;
3//Method 1:
4  sum = accumulate(v.begin(), v.end(), 0);
5//Method 2: 
6  for(auto& i : v) sum+=i;

1for (auto& n : vector)
2    sum_of_elems += n;

1 // Sum digits in vector
2int digit_sum(vector<int> num) {
3    int sum = 0;
4    for (auto x : num) sum += x;
5    return sum;
6}