Question

C++

1. Please use attached script for your reference to create the node structure and a linked list class, say LinkedList, that has the following basic member methods:
    constructor, destructor//IMPORTANT, display(), add_node().
2. Please implement the following additional member methods:
    Please feel free to change T with any data type you'd like to use for your node stricture's data type.
-- addFirst(T data) // Adds an node with data at the beginning of the list
-- pop() // Removes the first node of the list. Note: Don't forget to delete/re-allocate the dynamic memory
-- contains(T data) // return true or false if a node contains the data exists in the list
-- set(int index, T data) // update the data of the index'th node in the list with data.
-- size() // returns the number of nodes in the list
-- merge(LinkedList linkedlist) //merge this object with linkedlist object. In other words, add all nodes in linkedlist to this object.
Extra Credits:
-- insert(int index, T data) // Adds a node after the node with the 'index' number. Note, you will need to check if the node with the index number exists.
-- remove( int index) // Removes a node after the node with the 'index' number. Note, you will need to check if the node with the index number exists. Note: Don't forget to delete/re-allocate the dynamic memory
3. in main() // write some test code


#include <iostream>
using namespace std;

struct Node
{
    int data;
    Node *link;
};

class linked_list
{
private:
    Node *head,*current;
public:
     //constructor
    linked_list()
    {
        head = NULL;//the head pointer
        current = NULL;//acts as the tail of the list
    }

    //destructor - IMPORTANT
    ~linked_list() {
current = head;
while( current != NULL ) {//the loop stops when both current and head are NULL
    head = head->link;
    delete current;
    current = head;
}

    }

    void add_node(int n)// to add a node at the end of the list
    {
        Node *tmp = new Node;
        tmp->data = n;
        tmp->link = NULL;

        if(head == NULL)
        {
            head = tmp;
            current = tmp;
        }
        else
        {
            current->link = tmp;
            current = current->link;
        }
    }

    void display() // to display all nodes in the list
    {
        Node *tmp;
        tmp = head;
        while (tmp != NULL)
        {
            cout << tmp->data << endl;
            tmp = tmp->link;
        }
    }
};

int main()
{
    linked_list a;
    a.add_node(1);
    a.add_node(2);

a.display();


    return 0;
}

Answer 1

#include <iostream>

using namespace std;

struct Node

{

    int data;

  Node *link;

};

class linked_list

{

private:

    Node *head,*current;

public:

     //constructor

    linked_list()

    {

        head = NULL;//the head pointer

        current = NULL;//acts as the tail of the list

    }

    //destructor - IMPORTANT

    ~linked_list() {

               current = head;

               while( current != NULL )

               {//the loop stops when both current and head are NULL

                              head = head->link;

                              delete current;

                              current = head;

               }

   }

    void add_node(int n)// to add a node at the end of the list

    {

        Node *tmp = new Node;

        tmp->data = n;

        tmp->link = NULL;

        if(head == NULL)

        {

            head = tmp;

            current = tmp;

        }

        else

        {

            current->link = tmp;

            current = current->link;

        }

    }

    void display() // to display all nodes in the list

    {

        Node *tmp;

        tmp = head;

        while (tmp != NULL)

        {

            cout << tmp->data << endl;

            tmp = tmp->link;

        }

    }

    void addFirst(int n)// to add a node at the start of the list

    {

               Node *tmp = new Node;

               tmp->data = n;

               tmp->link = head;

               head = tmp;

               if(head->link == NULL)

                              current = head;

    }

    void pop()

    {

               if(head != NULL)

               {

                              Node *tmp = head;

                              head = head->link;

                              delete(tmp);

                              if(head == NULL)

                                             current = NULL;

               }

    }

    bool contains(int data)

    {

               Node *curr = head;

               while(curr != NULL)

               {

                              if(curr->data == data)

                                             return true;

                              curr = curr->link;

               }

               return false;

    }

    void set(int index, int data)

    {

               if(index >=0 && index < size())

               {

                              if(index == 0)

                                             head->data = data;

                              else

                              {

                                             Node *curr = head;

                                             int i=0;

                                             while(i < index)

                                             {

                                                            curr = curr->link;

                                                            i++;

                                             }

                                             curr->data = data;

                              }

               }

    }

    int size()

    {

               Node *curr = head;

               int count=0;

               while(curr != NULL)

               {

                              count++;

                              curr =curr->link;

               }

               return count;

    }

    void merge(const linked_list &linkedlist)

    {

               Node *curr = linkedlist.head;

               while(curr != NULL)

               {

                              add_node(curr->data);

                              curr = curr->link;

               }

    }

    void insert(int index, int data)

    {

               if(index >=0 && index <= size())

               {

                                             if(index == 0)

                                                            addFirst(data);

                                             else if(index == size())

                                                            add_node(data);

                                             else

                                             {

                                                            int i=0;

                                                            Node *curr = head;

                                                            Node *prev = NULL;

                                                            Node *tmp = new Node;

                                                            tmp->data = data;

                                                            tmp->link = NULL;

                                                            while(i < index )

                                                            {

                                                                           prev = curr;

                                                                           curr = curr->link;

                                                                           i++;

                                                            }

                                                            prev->link = tmp;

                                                            tmp->link = curr;

                                             }

               }

    }

    void remove( int index)

    {

               if(index >=0 && index < size())

               {

                              if(index == 0)

                              {

                                             pop();

                              }else

                              {

                                             int i=0;

                                             Node *curr = head;

                                             while(i < index-1)

                                             {

                                                            curr = curr->link;

                                                            i++;

                                             }

                                             Node *tmp = curr->link;

                                             curr->link = tmp->link;

                                             if(curr->link == NULL)

                                                            current = curr;

                                             delete(tmp);

                              }

               }

    }

};

int main() {

    linked_list a;

    a.add_node(1);

    a.add_node(2);

    a.addFirst(12);

    a.add_node(5);

    cout<<"List : "<<endl;

    a.display();

    cout<<"Size : "<<a.size()<<endl;

    if(a.contains(3))

               cout<<" list contains 3 "<<endl;

    else

               cout<<" list doesn't contains 3 "<<endl;

    if(a.contains(2))

               cout<<" list contains 2 "<<endl;

    else

               cout<<" list doesn't contains 2 "<<endl;

    a.set(1,4);

    cout<<"List : "<<endl;

    a.display();

    a.insert(2,7);

    cout<<"List : "<<endl;

    a.display();

    a.pop();

    cout<<"List : "<<endl;

    a.display();

    a.remove(2);

    cout<<"List : "<<endl;

    a.display();

    linked_list b;

    b.addFirst(34);

    b.addFirst(28);

    b.add_node(5);

    cout<<"List A : "<<endl;

    a.display();

    cout<<"List B : "<<endl;

    b.display();

    cout<<"B merged into A : "<<endl;

    a.merge(b);

    a.display();

   return 0;

}

//end of program

Output: