#include<stdio.h>
#include<stdlib.h>

struct stack{

int x;
struct stack *next;
}*top=NULL;

void push(int n){

struct stack *temp;
temp=(struct stack*)malloc(sizeof(struct stack));
temp->x=n;
if(top==NULL)
{
    temp->next=NULL;
    top=temp;
}
else{

    temp->next=top;
    top=temp;
}

}

void pop()
{

    if(top==NULL)
    {
        printf("The stack is underflow!!\n");
    }
    else{

        top=top->next;

    }
}
void display()
{
    struct stack *c=top;
    while(c!=NULL)
    {
        printf("%d\n",c->x);
        c=c->next;
    }
    printf("\n");


}
int main()
{
    push(11);
    display();
    push(7);
    display();
    push(5);
    display();
    pop();
    display();
    push(12);
    push(9);
    display();
    pop();
    display();
    pop();
    display();
    pop();
    display();

}