/* stack2.c */
/* use of linear list for stack */
#include <stdio.h>
#include <stdlib.h>

struct stack {
	int d;
	struct stack *next;
};

void push(int x, struct stack **s)
{
	struct stack *new_s;

	new_s = (struct stack*)malloc(sizeof(struct stack));
	new_s->next = *s;
	new_s->d    = x;
	*s = new_s;
}

void pop(int *xp, struct stack **s)
{
	struct stack *next_s;

	*xp = (*s)->d;
	next_s = (*s)->next;
	free(*s);
	*s = next_s;
}

int main()
{
	struct stack *sp;
	int x,y;

	sp = NULL;
	push(1,&sp);
	printf("%d %d %ld\n",x,y,(long int)sp);
	push(2,&sp);
	printf("%d %d %ld\n",x,y,(long int)sp);
	pop(&x,&sp);
	printf("%d %d %ld\n",x,y,(long int)sp);
	pop(&y,&sp);
	printf("%d %d %ld\n",x,y,(long int)sp);
	return(0);
}