1vector<int> a;
2vector<int> b;
3// Appending the integers of b to the end of a
4a.insert(a.end(), b.begin(), b.end());
1//vector.push_back is the function. For example, if we want to add
2//3 to a vector, it is just vector.push_back(3)
3vector <int> vi;
4vi.push_back(1); //[1]
5vi.push_back(2); //[1,2]