#include <iostream> //for the object cout
#include <cstdlib>  //for teh macro EXIT_SUCCESS
#include <list>     //for class list
using namespace std;

int main()
{
	list<int> li;        //born empty, but can hold ints
		       
	li.push_front(10);   //Insert at front of list.
	li.push_back(30);    //Insert at end of list.

	auto it {begin(li)}; //Iterator points at the first element of the list.
	++it;                //Iterator points at the second element of the list
	li.insert(it, 20);   //Insert 20 immediately before the second element.

	cout << "The list contains " << li.size() << " elements.\n\n";

	for (auto el: li) {  //Output all the elements of the list.
		cout << el << "\n";
	}

	return EXIT_SUCCESS;
}