#include<stdio.h>
#include<stdlib.h>
#include"ex1_stack.h"

void init_stack(struct stack * s)
{
    s->top = NULL;
};

void push(struct stack * s, int data)
{
    struct node * tmp = (struct node *) malloc(sizeof(struct node));
    if(tmp == NULL) {
         printf ("Remove items\n"); 
         return;
    } 
    tmp->data = data;
    tmp->prev = s->top;
    s->top = tmp;

    return;
}

int pop(struct stack * s)
{
   struct node * top = s->top;
   int i = top->data;

   s->top = top->prev;

   return i;
}


void print_stack(const struct stack * s)
{
   if (s->top == NULL)
     printf("\nEmpty Stack\n");
   else {
     printf("\nItems in Stack : ");

     struct node * tmp = s->top;
     while(tmp!=NULL) {
        printf(" %d ",tmp->data);
        tmp = tmp->prev;
     }

     printf("\n\n");
   }
   return;
}