//**************************************
//     
// Name: A Simple Linked List
// Description:A simple linked list exam
//     ple with various list operations. Demons
//     trates how to use a linked list class wi
//     th a separate Node class.
A good example for someone who want to learn about linked lists.
Please comment
// By: Maqsood
//
//This code is copyrighted and has// limited warranties.Please see http://
//     www.Planet-Source-Code.com/vb/scripts/Sh
//     owCode.asp?txtCodeId=13032&lngWId=3//for details.//**************************************
//     

#include <iostream.h>
#include <conio.h>


    class Node{
    private:
    int data;
    Node *nextNode; 
    
    public:
    void setData(int data)


        {
        this->data=data;
    } 

    int getData()


        {
        return data;
    }

    void setNext(Node *nextNode)


        {
        this->nextNode = nextNode; 
    } 

    Node *getNext()


        {
        return nextNode; 
    }

    
};




    class List{
    private:
    int size;
    Node *headNode;
    Node *currentNode;
    Node *lastCurrentNode;
    
    public:
    List();
    void addData(int data);
    void remove();
    void del(int pos, List l);
    void update(int pos, int newVal, List l);
    void search(int data, List l);
    void start();
    int get();
    bool next();
    void traverse(List);
    
};

List::List()


    {
    headNode = new Node();
    headNode->setNext(NULL);
    currentNode = NULL;
    lastCurrentNode = NULL;
    size = 0; 
}

void List::addData(int data)


    {
    Node *newNode = new Node();
    newNode->setData(data);
    
    if (currentNode == NULL)


        {
        headNode->setNext(newNode);
        newNode->setNext(NULL);
        lastCurrentNode = headNode;
        currentNode = newNode; 
    }

    else


        {
        newNode->setNext(currentNode->getNext());
        currentNode->setNext(newNode);
        lastCurrentNode = currentNode;
        currentNode = newNode;
    } 

    size++; 
}

void List::remove()


    {
    if (currentNode != NULL && size != 0)


        {
        lastCurrentNode->setNext(currentNode->getNext());
        delete currentNode;
        currentNode = lastCurrentNode; 
    }

    size--; 
}

bool List::next()


    {
    if (currentNode == NULL)
    return false;
    lastCurrentNode = currentNode;
    currentNode = currentNode->getNext(); 
    
    
    if (currentNode == NULL || size == 0)
    return false;
    else 
    return true; 
}

int List::get()


    {
    return currentNode->getData();
}

void List::traverse(List l)


    {
    Node *savedCurrentNode = l.currentNode;
    l.currentNode = l.headNode->getNext();
    
    for (int i = 1;l.next();i++)


        {
        cout<<"Element "<<i<<":"<<l.get()<<"\n"; 
    } 

    
    l.currentNode = savedCurrentNode; 
}

void List::search(int data, List l)


    {
    Node *savedCurrentNode = l.currentNode;
    l.currentNode = headNode->getNext(); 
    bool found = false;
    
    for(int i=1;l.next();i++)


        {
        if (l.get() == data)


            {
            cout<<"Element "<<data<<" found at position "<<i; 
            found = true; 
            break;
        }

    }

    
    if (!found)
    cout<<"Element does not exist in the list!";
    
    l.currentNode = savedCurrentNode;
}

void List::update(int pos, int newVal, List l)


    {
    Node *savedCurrentNode = l.currentNode;
    l.currentNode = headNode->getNext();
    //l.start();
    bool update=false;
    
    
    for (int i=1;l.next();i++)


        {
        if (i==pos)


            {
            l.currentNode->setData(newVal);
            cout<<"\nData updated "<<" at position "<<pos<<"\n";
            update = true;
            break;
        }

        
    }

    if (!update)
    cout<<"\n\nPosition does not exist";
    l.currentNode = savedCurrentNode;
}

void List::start()


    {
    currentNode = headNode;
    lastCurrentNode = headNode; 
}

void List::del(int pos, List l)


    {
    Node *savedCurrentNode = l.currentNode;
    l.currentNode = headNode->getNext();
    
    for (int i=1;l.next();i++)


        {
        if (pos == i)


            {
            l.lastCurrentNode->setNext(l.currentNode->getNext()); 
            delete l.currentNode;
            l.currentNode = l.lastCurrentNode;
            l.size--;
            cout<<"\n\n\n\nNode deleted\n\n";
            break;
        }

    }

    
    l.currentNode = savedCurrentNode;
}

main()


    {
    List l;
    
    l.addData(23);
    l.addData(45);
    l.addData(35);
    l.addData(12);
    l.addData(56);
    l.addData(11);
    l.addData(78);
    l.addData(99);
    //l.traverse(l);
    
    //l.remove();
    
    //cout<<"After removal: \n\n"; 
    //l.traverse(l);
    
    l.addData(101);
    //cout<<"After insertion: \n\n";
    //l.traverse(l);
    
    //l.search(45,l);
    
    l.addData(101);
    l.addData(102);
    l.addData(103);
    l.addData(104);
    
    l.traverse(l);
    
    /* l.update(5,117,l);
    
    cout<<"\n\n\nAfter Updation:\n";
    l.traverse(l);
    */
    
    //l.update(10,678,l);
    //l.traverse(l);
    //l.search(1026,l);
    
    //l.addData(32423);
    //l.traverse(l);
    
    l.del(7,l);
    
    l.traverse(l);
    getch();
}