Stack using Linked List in DSA C++

Program 1

// Stack Linked List
#include<iostream>
#include<stdio.h>
using namespace std;
class Node
{
    int data;
    Node *add;
    public:
    void create();
    void push();
    void pop();
    void display();
};Node *start=NULL,*new1,*temp,*prev1;
void Node::create()
{
      int n;
      cout<<"\n Enter an element: ";
      cin>>n;
      start=new Node();
      start->data=n;
      start->add=NULL;
      temp=start;
      char choice;
      cout<<"\n Want to continue(Y/y) : ";
      cin>>choice;
      while(choice=='y' ||choice=='Y')
      {
              cout<<"\n Enter next element: ";
             cin>>n;
             new1=new Node();
             new1->data=n;
             new1->add=NULL;
             temp->add=new1;
             temp=temp->add;
            cout<<"\n Want to continue(Y/y) : ";
           cin>>choice; 
      }
}
void Node::display()
{
     if(start==NULL)
       cout<<" Stack is empty";
     else
     {
        temp=start;
        while(temp!=NULL)
        {
              cout<<temp->data <<"    ";
              temp=temp->add;
        }
     }  
}
void Node::push()
{
     if(start==NULL)
       cout<<" Stack not created....";
     else
     {
           int n;
           cout<<"\n Enter an element: ";
          cin>>n;
          new1=new Node();
          new1->data=n;
          new1->add=NULL;
           temp=start;
           while(temp->add!=NULL)
           {
              temp=temp->add;
           }
           temp->add=new1;
     }

}

void Node::pop()
{
     if(start==NULL)
       cout<<" Stack is empty...";
      else
      {
        temp=start;
        while(temp->add!=NULL)
        {
             prev1=temp;
             temp=temp->add;
        }
        cout<<"Poped element is: "<<temp->data;
        prev1->add=NULL;
        delete temp;
      } 
}
int main()
{
       int ch;
       Node obj;
       system("cls");
    do
    {   
       cout<<"\n-----------Stack Linked List------------------";
       cout<<"\n 1. Create";
       cout<<"\n 2. Push";
       cout<<"\n 3. Pop";
       cout<<"\n 4. Display ";
       cout<<"\n 5.Exit";
       cout<<"\n------------------------------------------------";
       cout<<"\n Enter your choice: ";
       cin>>ch;
       switch(ch)
       {
           case 1:obj.create();break;
           case 2:obj.push();break;
           case 3:obj.pop();break;
           case 4: obj.display();break;

           case 5:break;
           default:cout<<"\n Invalid choice";
       }
    }while(ch!=5);
return 0;
}