Question

(I need an answer in c++ please / assignment question)

In a double linked chain, each node can point to the previous node as well as the next node.:

a. Define a class to represent a node in a doubly linked chain (UML)

b. Define a class to represent the doubly linked chain (UML), with operations such as:

1. finding its length.

2. add a new Node to the end of the chain.

3. check whether a given Node is included in the Chain (search a node)

4. another operation of your choice.

c. illustrate and list the steps to add to a node to the beginning of the doubly linked chain.

d. illustrate and list the steps necessary to remove the first noe from the doubly linked chain.

Answer 1

Screenshot

Program

dll.h

//Header file for I/O
#include<iostream>
using namespace std;
//Create a class Node
class Node {
public:
   int data;
   Node *prev;
   Node *next;
};
//Create a class for doubly linked list
class DoublyLL {
//Instance variable
private:
   Node *head;
public:
   //Constructor
   DoublyLL();
   //Insert at the end
   void insert(int newdata);
   //Print list in forward order
   void print();
   //Length of the list
   int findLength();
   //Search an element
   void searchNode(int data);
   //Print list in reverse order
   void printReverse();
   //Add element at the beginning
   void insertBeg(int val);
   //Delete first node
   void deleteFirst();
};
//Constructor
DoublyLL::DoublyLL() {
   head = nullptr;
}
//Insert at the end
void DoublyLL::insert(int newdata) {
   //Create ne node
   Node *newnode = new Node;
   newnode->data = newdata;
   newnode->prev = nullptr;
   newnode->next = nullptr;
   //list is empty
   if (head == nullptr)
       head = newnode;
   //Otherwise
   else {
       Node* ptr = head;
       while (ptr->next != nullptr) {
           ptr = ptr->next;
       }
       ptr->next = newnode;
       newnode->prev = ptr;
   }
}
//Print list in forward order
void DoublyLL::print() {
   Node* ptr = head;
   while (ptr != nullptr) {
       cout << ptr->data << " ";
       ptr = ptr->next;
   }
   cout << endl;
}
//Length of the list
int DoublyLL::findLength() {
   int cnt = 0;
   Node* ptr = head;
   while (ptr != nullptr) {
       cnt++;
       ptr = ptr->next;
   }
   return cnt;
}
//Search an element
void DoublyLL::searchNode(int data) {
   Node* ptr = head;
   int cnt = 0;
   while (ptr != nullptr) {
       cnt++;
       if (ptr->data == data) {
           cout << "Data found at the position " << cnt << endl;
           return;
       }
       ptr = ptr->next;
   }
   cout << "Data not found in the lsit" << endl;
}
//Print list in reverse order
void DoublyLL::printReverse() {
   Node* ptr = head;
   while (ptr->next != nullptr) {
       ptr = ptr->next;
   }
   while (ptr != NULL) {
       cout << ptr->data << " ";
       ptr = ptr->prev;
   }
   cout << endl;
}
//Add element at the beginning
void DoublyLL::insertBeg(int val) {
   Node* temp = head;
   //Create new node
   Node *newnode = new Node;
   newnode->data = val;
   newnode->prev = nullptr;
   newnode->next = temp;
   //Add into head
   head = newnode;
}
//Delete first node
void DoublyLL::deleteFirst() {
   //Head empty check
   if (head == nullptr) {
       cout << "List is empty!!" << endl;
   }
   //Head next empty check
   else if (head->next == nullptr) {
       head = nullptr;
   }
   //Otherwise
   else {
       head = head->next;
   }
}

main.cpp

#include "dll.h"
int main()
{
   //Create a doubly linked list
   DoublyLL dll;
   //Insert values into list
   dll.insert(10);
   dll.insert(2);
   dll.insert(5);
   //Display list
   cout << "Print list: ";
   dll.print();
   //Length of the list
   cout <<"Length of the list: "<<dll.findLength() << endl;
   //Reverse the list
   cout << "Reverse list: ";
   dll.printReverse();
   //Insert at the beginning
   dll.insertBeg(3);
   //Test
   cout << "Print after insert first: ";
   dll.print();
   //Delete
   cout << "Print after Deletion: ";
   dll.deleteFirst();
   dll.print();
}

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Output

Print list: 10 2 5
Length of the list: 3
Reverse list: 5 2 10
Print after insert first: 3 10 2 5
Print after Deletion: 10 2 5