stack

#include<stdio.h>
#include<stdlib.h>
typedef struct node
{
    int a;
    struct node *next,*prev;
}node;
node*head=NULL,*tail=NULL;
void PUSH(int a)
{
    node*p=(node*)malloc(sizeof(node));
    p->a=a;
    p->next=NULL;
    p->prev=NULL;

    if(head==NULL)
    {
        head=p;
        tail=p;
        return;
    }
   tail->next=p;
   p->prev=tail;
   p->next=NULL;
   tail=p;

}

int POP()
{ node*list;
    if(head==NULL)
    {
        printf("empty");
    }
    else
    {
        int temp;
        temp=tail->a;
        list=tail;
        list->prev->next=NULL;
        tail=list->prev;
        list->prev=NULL;
        free(list);
         return temp;

    }
}
int main()
{
   int n,x,y,i,s=0;
   scanf("%d",&n);
   for(i=0;i<n;i++)
   {
       scanf("%d",&x);
       PUSH(x);
   }
   scanf("%d",&y);
   for(i=0;i<y;i++)
   {
       s=POP();
       printf("%d ",s);
   }
}