Question

Define a struct Node to represent a node in a double linked-list that stores a string as data. Write a function to insert a node to the head of the linked list. The function takes two arguments: a pointer to the first node in the double linked list and a string value. It should create a new node with the given value to the head of the double linked list.

Answer 1

//C++ program

#include<iostream>
using namespace std;

struct Node{
   string data;
   struct Node*prev;
   struct Node*next;
};

void insert(struct Node**head , string data){
   struct Node *newNode = new Node;
   newNode->data = data;
   newNode->prev = NULL;
   newNode->next = NULL;
  
   if(*head !=NULL) (*head)->prev = newNode;
   newNode->next = *head;
   *head = newNode;
}

void display(struct Node*head){
   while(head){
       cout<<head->data<<" ";
       head = head->next;
   }
   cout<<"\n";
}

int main(){
   struct Node *head = NULL;
   insert(&head,"World");
   display(head);
   insert(&head,"Hello");
   display(head);
   return 0;
  
}