#include<stdio.h>

struct list{

   int data;
   struct list *next;
};
typedef struct list node;

node *top=NULL;

int peek()
{
    if(top==NULL)
    {
        printf("STACK IS EMPTY\n");
         return -1;
    }
    return top->data;

}
void display()
{
    node *temp;
    temp=top;
        if(top==NULL)
    {
        printf("STACK IS EMPTY\n");
    }
    else{
        while(temp!=NULL)
        {
            printf("ELEMENTS ARE:%d ",temp->data);
            temp=temp->next;
        }
    }

}

void push(int item)
{
    node *new_node;
    new_node = new node();

    new_node->data=item;
    new_node->next=top;
    top=new_node;
}
void pop()
{
    if(top==NULL)
    {
        printf("STACK IS EMPTY\n");
    }
    else{
        top=top->next;
    }
}


int main()
{
    push(5);
    push(10);
    push(20);
    int x=peek();
    printf("TOP IS : %d ",x);
    printf("\n");
    display();
    pop();
      pop();
    printf("\n");
    display();
}