Linked_List_stack_implementation

#include <iostream>
using namespace std;

class node;
node* head=NULL;
//node* ptr=head;
class node
{
private:
    int data;
public:
    void setvalue(int x)
    {
        data=x;
    }
    int getvalue()
    {
        return data;
    }
    node* ptrnext;

    void display()
    {
        node* ptr=head;
        while(ptr!=NULL)
        {
            cout<<ptr->data<<" ";
            ptr=ptr->ptrnext;
        }
        cout<<endl<<endl;
    }
    ////////////////////////////////////////////////////////////
    void search_item(int item)
    {
         node* ptr=head;
	while(ptr->data != item && ptr-> ptrnext !=NULL)
		ptr = ptr->ptrnext;
	if(ptr->data==item)
		cout<<item<<" "<<"Found"<<endl;
	else
		cout<<item<<" "<<"Not Found"<<endl;

    }
    ///////////////////////////////////////////////////////////
    void ensert_end_stack(int k,node* newn)
    {
        newn->data=k;
        newn->ptrnext=NULL;
    }
    /////////////////////////////////////////////////////////
    void delete_end_stack()
    {
        node* ptr=head;
        node* ptr2;
	    while(ptr->ptrnext->ptrnext!=NULL)
		ptr=ptr->ptrnext;
	    ptr2=ptr->ptrnext;
	    ptr->ptrnext = NULL;
    }
};
int main()
{
    node n1,n2,n3,n4;
    n1.setvalue(10);
    n2.setvalue(20);
    n3.setvalue(30);
    head=&n1;
    n1.ptrnext=&n2;
    n2.ptrnext=&n3;
    n3.ptrnext=NULL;
    cout<<"Existing Linked List : ";
    n1.display();

    int search_value;
    cout<<"Insert data to search : ";
    cin>>search_value;
    cout<<endl;
    n1.search_item(search_value);
    cout<<endl;

    int add_value;
    node* newnode;
    newnode=&n4;
    cout<<"Insert data to add : ";
    cin>>add_value;
    cout<<endl;
    n3.ptrnext=&n4;
    n4.ensert_end_stack(add_value,newnode);
    cout<<"After insertion : ";
    n4.display();
    cout<<endl;

    n4.delete_end_stack();
    cout<<"After Deletion : ";
    n1.display();

    return 0;
}