#include "pile.h"

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

void init( struct Pile* p ) {
    p->height = 0;
    p->l = NULL;
}

void push( struct Pile* p, struct NumContainer i ) {
    struct List* aux = p->l;

    p->l = (struct List*)malloc(sizeof(struct List));
    if (p->l == NULL) {
        fprintf(stderr, "Error: Could not allocate memory for the next cell on the stack\n");
        return;
    }

    p->l->next = aux;
    p->l->i = i;
    ++(p->height);
}

struct NumContainer top( struct Pile* p ) {
    if ( p->height == 0 ) {
        fprintf(stderr, "Error: The stack has no element, cannot find top\n");
        exit(1);
    }
    return p->l->i;
}

void print( struct Pile* p ) {
    struct List* aux = p->l;

    while (aux != NULL) {
        printNum(aux->i);
        printf(" ");
        aux = aux->next;
    }
    /* printf("NULL"); */
}

void pop( struct Pile* p ) {
    struct List* aux;

    if ( p->height != 0 ) {
        --(p->height);
        aux = p->l;
        p->l = p->l->next;
        free(aux);
    }
}

void end( struct Pile* p ) {
    while (p->height != 0) {
        pop(p);
    }
}

void getlastnums( struct NumContainer* i, struct NumContainer* j, struct Pile* pile ) {
    *j = top(pile);
    pop(pile);
    *i = top(pile);
    pop(pile);
}