#include<iostream>
using namespace std;
class node{
    public:
    node*next;
   
    int data;
    node(int val){
        data=val;
        next=NULL;
        

    }
};

void insertatTail(node*&head, int val){
    node*n=new node(val);
    if(head==NULL){
        head=n;
        return;
    }
    node*temp=head;

    while(temp->next!=NULL){
        temp = temp->next;
    }
    temp->next=n;
    
    
}
void insertatHead(node*&head, int val){
    node*n = new node(val);
    n->next=head;
    head=n;

}

void display(node*head){
    node*temp = head;
    while(temp!=NULL){
        cout<<temp->data<<" ";
        temp=temp->next;
    }
    cout<<endl;
}

int main(){
    node*head=NULL;
    insertatTail(head,1);
    insertatTail(head,2);
    insertatTail(head,3);
    insertatTail(head,4);
    insertatTail(head,5);
    insertatTail(head,6);
    display(head);
    insertatHead(head,9);
    insertatHead(head,10);
    display(head);


    return 0;
    
   

    

}
