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

typedef struct node {
int element;
struct node *next;
} node;

// Head refers to a pointer to a node.
typedef node* head;

typedef struct list {
head head;
} list;

void push(list *existing_list, int element) {
node *new_node = malloc(sizeof(node));
new_node->element = element;
new_node->next = existing_list->head;
existing_list->head = new_node;
}

int pop(list *existing_list){
int elem = existing_list->head->element;
free(existing_list->head);
existing_list->head = existing_list->head->next;
return elem;
}

int main(){
list initial_list;
push(&initial_list, 2);
push(&initial_list, 3);
printf("%i\n", pop(&initial_list));
printf("%i\n", pop(&initial_list));
return 0;
}