Doubly Linked List

doublyLinkedList.cpp

//Milad Abbasi
//06-07-2018
//Doubly Linked List

#include <iostream>
using namespace std;

class Node
{
public:
	int data;
	Node *next;
	Node *prev;
};

class DoublyLinkedList
{
	Node *head;
	Node *tmp;
public:
	DoublyLinkedList()
	{
		head = NULL;
	}

	void insertStart(int value)
	{
		tmp = new Node;
		tmp->data = value;
		tmp->prev = NULL;

		if(isEmpty())
			tmp->next = NULL;
		else
			tmp->next = head;

		head = tmp;
	}

	void insertEnd(int value)
	{
		tmp = new Node;
		tmp->data = value;
		tmp->next = NULL;

		if(isEmpty())
		{
			tmp->prev = NULL;
			head = tmp;
		}
		else
		{
			Node *last = new Node;
			last = head;
			while(last->next != NULL)
				last = last->next;

			last->next = tmp;
			tmp->prev = last;
		}
	}

	void insertAfter(int pos, int value)
	{
		tmp = new Node;
		tmp->data = value;
		if(isEmpty())
		{
			tmp->next = NULL;
			tmp->prev = NULL;
			head = tmp;
		}
		else
		{
			Node *current = new Node;
			current = head;
			for(int i = 1; i < pos; i++)
				current = current->next;

			tmp->prev = current;
			tmp->next = current->next;
			if(current->next != NULL)
				current->next->prev = tmp;
			current->next = tmp;

		}
	}

	void deleteStart()
	{
		if(isEmpty())
		{
			cout<<"List is empty";
			return;
		}
		tmp = head;
		head = head->next;
		head->prev = NULL;
		delete tmp;
	}

	void deleteEnd()
	{
		if(isEmpty())
		{
			cout<<"List is empty";
			return;
		}
		tmp = head;
		while(tmp->next != NULL)
			tmp = tmp->next;

		tmp->prev->next = NULL;
		delete tmp;
	}

	void deletePosition(int pos)
	{
		if(isEmpty())
		{
			cout<<"List is empty";
			return;
		}
		tmp = head;
		for(int i = 1; i < pos; i++)
			tmp = tmp->next;

		tmp->prev->next = tmp->next;
		tmp->next->prev = tmp->prev;
		delete tmp;
	}

	bool isEmpty()
	{
		return head == NULL;
	}

	void print()
	{
		Node *tmp = new Node;
		tmp = head;
		while(tmp)
		{
			cout<<tmp->data<<"\t";
			tmp = tmp->next;
		}
	}
	
};