gistfile1.cpp

#include <iostream>

using namespace std;

template <class E>
class LinkedList
{
	struct Node;
	
	Node* first;
	Node* last;

public:
	
	struct Node
	{
		Node* prev;
		Node* next;
		E data;
	};
	
	class iterator
	{
		Node* thiz;
	public:
		iterator(Node* ptr)
		{
			thiz = ptr;
		}
		E& operator*()
		{
			return thiz->data;
		}
		iterator operator++()
		{
			thiz = thiz->next;
			return *this;
		}
		iterator operator--()
		{
			thiz = thiz->prev;
			return *this;
		}
		bool operator!=(const iterator& other) const
		{
			return thiz != other.thiz;
		}
		bool operator==(const iterator& other) const
		{
			return thiz == other.thiz;
		}
	};
	
	E& front()
	{
		return (*first).data;
	}
	E& back()
	{
		return last->prev->data;
	}
	iterator begin()
	{
		return iterator{ first };
	}
	iterator end()
	{
		return iterator{ last };
	}
	
	void reverse()
	{
		Node* current = first;

		while (current != last)
		{
			Node* temp = current->next;
			swap(current->prev, current->next);
			current = temp;
		}

		Node* new_first = last->prev;

		first->next = last;
		last->prev = first;

		first = new_first;
	}

	void push_back(const E& val)
	{
		Node* new_last = new Node();

		last->data = val;
		last->next = new_last;

		new_last->prev = last;
		new_last->next = NULL;

		last = new_last;
	}

	void pop_back()
	{
		Node* new_last = last->prev;

		delete last;

		last = new_last;
		last->next = NULL;
	}

	void pop_front()
	{
		Node* new_first = first->next;

		delete first;

		first = new_first;
		first->prev = NULL;
	}

	LinkedList()
	{
		first = new Node();

		first->prev = NULL;
		first->next = NULL;

		last = first;
	}

	~LinkedList()
	{
		Node* toDelete = first;
		Node* next;

		do
		{
			next = toDelete->next;
			delete toDelete;
			toDelete = next;
		} while (toDelete);
	}

};

int main()
{
	LinkedList<int> t{};
	t.push_back(2);
	t.push_back(5);
	t.push_back(9);
	t.push_back(11);
	t.push_back(25);
	t.push_back(49);

	for (auto& i : t)
	{
		cout << i << endl;
	}

	cout << endl;

	t.reverse();

	for (auto& i : t)
	{
		cout << i << endl;
	}

	cout << endl;

	LinkedList<int>::iterator it = t.begin();

	for (; it != t.end(); ++it)
	{
		cout << *it << endl;
	}

	--it;

	cout << endl;

	for (;; --it)
	{
		cout << *it << endl;
		if (it == t.begin()) break;
	}

	cout << endl;

	t.pop_back();
	t.pop_back();
	t.pop_front();
	t.pop_front();

	t.push_back(11);
	t.push_back(13);

	for (auto& i : t)
	{
		cout << i << endl;
	}

	cout << endl;

	t.back() -= t.front();

	cout << t.back();

	cout << endl;

	system("pause");
}