c++ vector add all elements code example

Example 1: how to append one vector to another c++

vector<int> a;
vector<int> b;
// Appending the integers of b to the end of a 
a.insert(a.end(), b.begin(), b.end());

Example 2: sum elements in vector c++

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