Question

I want the linked list to be inserted by the user and donot use getline to insert it

#include <bits/stdc++.h>

using namespace std;

  

// A linked list Node

struct Node {

    int data;

    struct Node* next;

};

  

// Size of linked list

int size = 0;

  

// function to create and return a Node

Node* getNode(int data)

{

    // allocating space

    Node* newNode = new Node();

  

    // inserting the required data

    newNode->data = data;

    newNode->next = NULL;

    return newNode;

}

  

// function to insert a Node at required position

void insertPos(Node** current, int pos, int data)

{

    // This condition to check whether the

    // position given is valid or not.

    if (pos < 1 || pos > size + 1)

        cout << "Invalid position!" << endl;

    else {

  

        // Keep looping until the pos is zero

        while (pos--) {

  

            if (pos == 0) {

  

                // adding Node at required position

                Node* temp = getNode(data);

  

                // Making the new Node to point to

                // the old Node at the same position

                temp->next = *current;

  

                // Changing the pointer of the Node previous

                // to the old Node to point to the new Node

                *current = temp;

            }

            else

              // Assign double pointer variable to point to the

              // pointer pointing to the address of next Node

              current = &(*current)->next;

        }

        size++;

    }

}

  

// This function prints contents

// of the linked list

void printList(struct Node* head)

{

    while (head != NULL) {

        cout << " " << head->data;

        head = head->next;

    }

    cout << endl;

}

  

// Driver Code

int main()

{

    // Creating the list 3->5->8->10

    Node* head = NULL;

    head = getNode(3);

    head->next = getNode(5);

    head->next->next = getNode(8);

    head->next->next->next = getNode(10);

  

    size = 4;

  

    cout << "Linked list before insertion: ";

    printList(head);

  

    int data = 12, pos = 3;

    insertPos(&head, pos, data);

    cout << "Linked list after insertion of 12 at position 3: ";

    printList(head);

  

    // front of the linked list

    data = 1, pos = 1;

    insertPos(&head, pos, data);

    cout << "Linked list after insertion of 1 at position 1: ";

    printList(head);

  

    // insetion at end of the linked list

    data = 15, pos = 7;

    insertPos(&head, pos, data);

    cout << "Linked list after insertion of 15 at position 7: ";

    printList(head);

  

    return 0;

}

Answer 1

#include <bits/stdc++.h>

using namespace std;

// A linked list Node

struct Node {

    int data;

    struct Node* next;

};

// Size of linked list

int size = 0;

// function to create and return a Node

Node* getNode(int data)

{

    // allocating space

    Node* newNode = new Node();

    // inserting the required data

    newNode->data = data;

    newNode->next = NULL;

    return newNode;

}

// function to insert a Node at required position

void insertPos(Node** current, int pos, int data)

{

    // This condition to check whether the

    // position given is valid or not.

    if (pos < 1 || pos > size + 1)

        cout << "Invalid position!" << endl;

    else {

        // Keep looping until the pos is zero

        while (pos--) {

            if (pos == 0) {

                // adding Node at required position

                Node* temp = getNode(data);

                // Making the new Node to point to

                // the old Node at the same position

                temp->next = *current;

                // Changing the pointer of the Node previous

                // to the old Node to point to the new Node

                *current = temp;

            }

            else

              // Assign double pointer variable to point to the

              // pointer pointing to the address of next Node

              current = &(*current)->next;

        }

        size++;

    }

}

// This function prints contents

// of the linked list

void printList(struct Node* head)

{

    while (head != NULL) {

        cout << " " << head->data;

        head = head->next;

    }

    cout << endl;

}

// Driver Code

int main()

{

    // Creating the list 3->5->8->10

    Node* head = NULL;
    Node* current = head;
    int n;
    cout<<"enter no of values you want to enter to initialize the linked list:\t";
    cin>>n;
    for(int i = 0; i < n;i++)
    {
   cout<<"enter value:\t";
   int ele;
   cin>>ele;
   Node* newNode = getNode(ele);
   if(head == NULL)
   {
       head = newNode;
   }
   else
   {
       current = head;
       while(current -> next != NULL)
       {
           current = current -> next;
       }
       current -> next = newNode;
   }
   size++;
    }
    printList(head);
    int data, pos;
    int ch;
    cout<<"want to enter element with position (1 - yes/ 0 - no) :\t";
    cin>>ch;
    while(ch != 0)
    {
   cout<<"enter value:\t";
        cin>>data;
        cout<<"enter position:\t";
        cin>>pos;
        insertPos(&head, pos, data);
        printList(head);
        cout<<"want to insert one more (1 - yes/ 0 - no) :\t";
   cin>>ch;
    }
    return 0;
}

If you have any doubts please comment and please don't dislike.