Question

class Node public: double v Node next;/ Points to the nert Node Node *prev/ Points to the previous Node class LList Node head public: void addNode (double v); // Add a node to the end of the link list //Member Functions here ti

***Using C++ and also please label "a" and "c" accordingly. Thank you!!****

a) Write the member function void deleteNode() that will delete the first node from the linked list.

b) Modify the LList to create a data member Node *cur that points to the current node. Write the following member functions:

• void forward() that moves the cur pointer to the next node.

• void backward() that moves the cur pointer to the previous node.

• void delete() that removes the node that is pointed to by the cur pointer. ( Think of how you will set the cur pointer after the delete and state your strategy.)

• double getValue() that returns the value of the node that is pointed to by the cur pointer.

c) Write the member function Node *findFirstNodeByValue(double x) that will return the reference of the first node that has the value x. You start your search from the pointer cur.

Answer 1

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <iomanip>

using namespace std;

//Node Class
class Node{
public:
    double v;
    Node *next;
    Node *prev;
};

//LinkedList class
class LList{
    //Head pointer
    Node *head=nullptr;
public:
    //Current pointer
    Node *cur = nullptr;
    //This adds a new node at the end of linked list
    void addNode(double val){
        Node *nnode = new Node();
        nnode->v = val;
        if(head==nullptr){
            head = nnode;
            cur = nnode;
            return;
        }
        Node *temp = head;
        //Move to the end and add new node
        while(temp->next!=nullptr){
            temp = temp->next;
        }
        temp->next = nnode;
        nnode->prev = temp;
    }

    //This deletes head node
    void deleteNode(){
        if(head==nullptr){
            return;
        }
        Node *temp = head;
        head = head->next;
        head->prev = nullptr;
        cur = head;
        free(temp);
    }

    void forward(){
        cur = cur->next;
    }

    void backward(){
        cur = cur->prev;
    }

    //This deletes current node
    void deleteCurrent(){
        if(cur==head){
            deleteNode();
            return;
        }
        Node *del = cur;
        Node *prev = cur->prev;
        Node *next = cur->next;
        prev->next = next;
        next->prev = prev;
        free(del);
    }

    double getValue(){
        return cur->v;
    }

    //This finds node by value
    Node * findFirstNodeByValue(double x){
        Node *temp = cur;
        while(temp!=nullptr){
            if(temp->v==x){
                return temp;
            }
            temp = temp->next;
        }
        return nullptr;
    }

    //This prints the linked list
    void print(){
        Node *temp = head;
        while(temp!=nullptr){
            cout<<temp->v<<"->";
            temp = temp->next;
        }
        cout<<"NULL"<<endl;
    }
};

int main(){
    LList a;
    a.addNode(3);
    a.addNode(4);
    a.addNode(5);
    a.addNode(6);
    a.addNode(7);
    a.addNode(8);
    a.print();
    a.deleteNode();
    a.print();
    cout<<"Current "<<a.cur->v<<endl;
    a.forward();
    a.forward();
    a.forward();
    a.backward();
    cout<<"Current "<<a.cur->v<<endl;
    a.deleteCurrent();
    a.print();

    return 0;
}

OUTPUT :

"D\CodingiCODE BLOCKSSampleCpplbin\DebuglSampleCpp.exe" 3->4->5->6->7->8->NULL 4->5->6->7-8->NULL Current 4 Current 6 ->5->7->8->NULL Process returned e (exe) execution ti Press any key to continue. me : 0.090 s