vector<int> v;
cout << v[v.size() - 1];
cout << *(v.end() - 1);
cout << *v.rbegin();
// all three of them work
vector<int> vec;
vec.push_back(0);
vec.push_back(1);
int last_element = vec.back();
int also_last_element = vec[vec.size() - 1];
std::v.back()
int var = vec.back().c;