Doubly linked list in C

// Dvostruko spregnuta lista
// dmarjanovic

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

typedef struct Node ListNode;

struct Node {
     // Pokazivac na prethodni i pokazivac na sljedeci
     ListNode *prev;
     ListNode *next;
     int element;
};

// Inicijalizacija liste
void initialize_list(ListNode **head, ListNode **tail) {
     // Pokazivac na "glavu" i na "rep" list postavimo na NULL
     *head = NULL;
     *tail = NULL;
}

// Dodavanje novog elementa u listu
void add_element(ListNode **head, ListNode **tail, int element_data) {
     ListNode *new_node;
     new_node = (ListNode *)malloc(sizeof(ListNode));
     new_node -> element = element_data;
     new_node -> next = NULL;

     // Prvi element liste
     if (*head == NULL && *tail == NULL) {
        new_node -> prev = NULL;
        *head = new_node;
        *tail = new_node;
        return;
    }

    ListNode *current;
    current = *tail;

    new_node -> prev = current;
    current -> next = new_node;
    *tail = new_node;
}

// Brisanje elementa liste
void delete_element(ListNode **head, ListNode **tail, int element_data) {
     ListNode *current;

    current = *head;

    while (current != NULL) {
        if (current -> element == element_data) {
            current -> prev -> next = current -> next;
            current -> next -> prev = current -> prev;
            free(current);
            return;
        }

        current = current -> next;
    }
}

// Stampanje elemenata liste
void print_list(ListNode **head, ListNode **tail) {
     ListNode *current;

     current = *head;

     while (current != NULL) {
           printf("Element je: %d \n", current -> element);
           current = current -> next;
     }

     printf("\n");
}

int main() {

    ListNode *head;
    ListNode *tail;
    initialize_list(&head, &tail);

    add_element(&head, &tail, 4);
    add_element(&head, &tail, 23);
    add_element(&head, &tail, 7);
    add_element(&head, &tail, 1);
    add_element(&head, &tail, 2);

    print_list(&head, &tail);

    delete_element(&head, &tail, 1);

    print_list(&head, &tail);

    system("PAUSE");

    return 0;
}