Question

1. Write a function to implement linked list consisting of five nodes. Store the data in the nodes in the order given below. Also, write a function to display the data stored in the implemented linked list. in C++ programming

George, Paul, Ross, Joe, Elaine, Robert1

2. Insert three nodes in between second node and third node in the linked list that you implemented in problem 1. Store the following data in the new (inserted) nodes in the following order. (You have to write a function for insertion operation, in C++ programming).

                               Davis1, Davis2, Davis3

3. Delete a node (data and the node together) from the linked list that you implemented in problem 2. (You have to write a function for delete operation, in C++ Programming).

Answer 1

Answer:

#include<iostream>

using namespace std;

// Node Declaration

struct node
{

    string data;

    struct node *next;

}*start;

//class declaration

class single_llist
{
    public:

        node* create_node(string);
        void insertFirst(string);
        void insert_pos(string);
        void delete_pos();
        void display();
        single_llist()
        {
            start = NULL;
        }
};

int main()

{
    single_llist s1;

    int choice;

    single_llist sl;

    start = NULL;

    cout<<"Inserting nodes initially";

    sl.insertFirst("Robert1");
    sl.insertFirst("Joe");
    sl.insertFirst("Ross");
    sl.insertFirst("Paul");
    sl.insertFirst("George");
    sl.display();

    s1.insert_pos("Davis3");
    s1.display();
    s1.insert_pos("Davis2");
    s1.display();
    s1.insert_pos("Davis1");
    sl.display();

    sl.delete_pos();
    sl.display();

   return 0;

}

/*

* Creating Node

*/

node *single_llist::create_node(string value)

{

    struct node *temp, *s;

    temp = new(struct node);

    if (temp == NULL)

    {

        cout<<"Memory not allocated "<<endl;

        return 0;

    }

    else

    {

        temp->data = value;

        temp->next = NULL;

        return temp;

    }

}

void single_llist::insertFirst(string value)

{

   struct node *temp, *p;

    temp = create_node(value);

    if (start == NULL)

    {

        start = temp;

        start->next = NULL;

    }

    else

    {

        p = start;

        start = temp;

        start->next = p;

    }

    cout<<endl<<"Element "<<value<<" Inserted "<<endl;

}

/*

* Insertion of node at a given position

*/

void single_llist::insert_pos(string value)

{

    int pos, counter = 0;

    struct node *temp, *s, *ptr;

    temp = create_node(value);

    cout<<"\nEnter the position at which node to be inserted: ";

    cin>>pos;

    int i;

    s = start;

    while (s != NULL)

    {

        s = s->next;

        counter++;

    }

    if (pos == 1)

    {

        if (start == NULL)

        {

            start = temp;

            start->next = NULL;

        }

        else

        {

            ptr = start;

            start = temp;

            start->next = ptr;

        }

    }

    else if (pos > 1 && pos <= counter)

    {

        s = start;

        for (i = 1; i < pos; i++)

        {

            ptr = s;

            s = s->next;

        }

        ptr->next = temp;

        temp->next = s;

    }

    else

    {

        cout<<"Position out of range"<<endl;

    }

}

/*

* Delete element at a given position

*/

void single_llist::delete_pos()

{

    int pos, i, counter = 0;

    if (start == NULL)

    {

        cout<<"List is empty"<<endl;

        return;

    }

    cout<<"\nEnter the position of value to be deleted: ";

    cin>>pos;

    struct node *s, *ptr;

    s = start;

    if (pos == 1)

    {

        start = s->next;

    }

    else

    {

        while (s != NULL)

        {

            s = s->next;

            counter++;

        }

        if (pos > 0 && pos <= counter)

        {

            s = start;

            for (i = 1;i < pos;i++)

            {

                ptr = s;

                s = s->next;

            }

            ptr->next = s->next;

        }

        else

        {

            cout<<"Position out of range"<<endl;

        }

        free(s);

        cout<<"\nElement Deleted"<<endl;

    }

}

/*

* Display Elements of a link list

*/

void single_llist::display()

{

    struct node *temp;

    if (start == NULL)

    {

        cout<<"\nThe List is Empty"<<endl;

        return;

    }

    temp = start;

    cout<<"\nElements of list are: "<<endl;

    while (temp != NULL)

    {

        cout<<temp->data<<"->";

        temp = temp->next;

    }

    cout<<"NULL"<<endl;

}

Output: