Description : The list::back() function in C++ STL returns a direct reference to the last element in the list container.
Example:
// Initialization of list
std::list<int> demo_list;
// Adding elements to the list
demo_list.push_back(10);
demo_list.push_back(20);
demo_list.push_back(30);
// prints the last element of demo_list
std::cout << demo_list.back();