When I am trying to enter a node between doubly circular linked list it gives wrong output

Question

Here I created a doubly circular linked list and try to add a node between the list but it is giving wrong output

I first created a doubly circular linked list and then displayed it and then I added a node between them and then again displayed it

#include<iostream>
using namespace std;
class node                                  //node class
{
public:
    int data;
    node *next;
    node *prev;
    node(int a)
    {
        data=a;
        next=nullptr;
        prev=nullptr;
    }
};
class linkedlist                            //linkedlist class
{
    node *head,*tail;
public:
    linkedlist()
    {
        head=nullptr;
        tail=nullptr;
    }
    void addnode(int val)                   //creating node function
    {
        node *newnode;
        newnode=new node(val);
        if(head==0)
            head=tail=newnode;
        else
        {
            tail->next=newnode;
            head->prev=newnode;
            newnode->prev=tail;
            newnode->next=head;
            tail=newnode;
        }
    }
    void disp()                             //display function
    {
        node *temp=head;
        while(temp->next!=head)
        {
            cout<<temp->data<<"   ";
            temp=temp->next;
        }
        temp=temp->next;
        cout<<"   "<<temp->data;
    }
    void addin(int val,int pos)             //addin function
    {
        node *newnode=new node(val);
        node *temp=head;
        for(int i=0;i<pos;i++)
            {
                temp=temp->next;
            }
        newnode->next=temp->next;
        newnode->prev=temp;
        temp->next->prev=newnode;
        temp->next=newnode;
    }
};
int main()
{
    linkedlist l1;
    int s,val,val1,pos;
    cin>>s;
    for(int i=0;i<s;i++)
    {
        cin>>val;
        l1.addnode(val);
    }
    l1.disp();                              //display function
    cout<<"\n\n";
    cin>>pos;
    cin>>val1;
    l1.addin(val,pos);                      //calling addin function
    l1.disp();
}

Input

3

1 2 3

1

0

Expected output

1  2  3

1 2 0 3

Current output

1  2  3   1

I don't know what mistake I am doing and also I am beginner so any tip is also too helpful for me

Answer 1

• You are printing the head node instead of the tail node due to the extra temp=temp->next; after the loop in the disp() function.
• You are adding val instead of val1 after the loop in the main() function.

    void disp()                             //display function
    {
        node *temp=head;
        while(temp->next!=head)
        {
            cout<<temp->data<<"   ";
            temp=temp->next;
        }
        // remove this
        // temp=temp->next;
        cout<<"   "<<temp->data;
    }

    cin>>pos;
    cin>>val1;
    // add val1, not val
    //l1.addin(val,pos);                      //calling addin function
    l1.addin(val1,pos);                      //calling addin function
    l1.disp();