#include <stdlib.h>
#include "stack.h"

//TODO: grundlegende Stackfunktionen implementieren:
/*  * `push`: legt ein Element oben auf den Stack,
    * `pop`: entfernt das oberste Element,
    * `top`: liefert das oberste Element zurück,
    * `clearStack`: gibt den gesamten Speicher frei. */

// Pushes data as pointer onto the stack.
static StackNode *createEmptyElement()
{
    return malloc(sizeof(StackNode));
}
StackNode *push(StackNode *stack, void *data)
{
    StackNode *newElement = createEmptyElement();
    newElement->data = data;
    newElement->next = NULL;
    if (stack == NULL)
    {
        stack = newElement;
    }
    else
    {
        StackNode *currentElement = stack;
        while(currentElement->next != NULL)
        {
            currentElement = currentElement->next;
        }
        currentElement->next = newElement;
    return stack;
    }
}

// Deletes the top element of the stack (latest added element) and releases its memory. (Pointer to data has to be
// freed by caller.)
StackNode *pop(StackNode *stack)
{

}

// Returns the data of the top element.
void *top(StackNode *stack)
{

}

// Clears stack and releases all memory.
void clearStack(StackNode *stack)
{

}