#include <iostream>
using namespace std;

class Single_list
{
private:
	struct Single_node
	{
		Single_node* next;
		int val;
		Single_node(int val, Single_node* next = nullptr)
		{
			this->val = val;
			this->next = next;

		}
		Single_node() {}

	};

	int Size;
	Single_node* head;
	Single_node* tail;

public:
	Single_list()
	{
		head = nullptr;
		Size = 0;
	}

	Single_list(int val)
	{
		Single_node(val, nullptr);
		Size = 1;
	}

	void push_front(int val)
	{
		head = new Single_node(val,head);
		Size++;
	}

	void pop_front()
	{
		Single_node *temp = head;
		head = head->next;
		delete temp;
		Size--;
	}

	void clear()
	{
		while (Size)
			pop_front();
	}

	~Single_list()
	{
		clear();
	}

	int size()
	{
		return Size;
	}

	bool empty()
	{
		if (Size == 0)
			return 1;
		else
			return 0;
	}

	void print()
	{
		Single_node* p = head;
		while (p) {
			cout << p->val << ' ';
			p = p->next;
		}
		cout << endl;
	}

	int& front()
	{
		return head->val;
	}

};





int main()
{
	Single_list list;
	for (int i = 0; i < 5; i++)
	{
		list.push_front(i);
		list.print();
	}
	while (!list.empty())
	{
		list.print();
		list.pop_front();

	}


}