#include <iostream>

using namespace std;

 struct node
{
        int data;
        struct node *link;
};

struct node *top=NULL;


void push(int x)
    {
        struct node *N = new node;
        N->data=x;
        N->link=NULL;

        if(top==NULL)
        {
            top=N;
        }
        else
        {
            N->link=top;
            top=N;
        }
    }


void pop()
    {
        if(top==NULL)
        {
            cout<<"There's no values in the list"<<endl;
        }
        else
        {
            top=top->link;

        }
    }

    void display()
    {
        struct node *t =top;
        while(t->link!=NULL)
        {
            cout<<t->data<<"->";
            t=t->link;
        }
        cout<<t->data<<endl;
    }

int main()
{
    push(10);
    push(20);
    push(30);
    display();
    pop();
    display();

    return 0;
}