C프 linked list

linkedlist.c

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

typedef struct _node NODE;
typedef struct _list LIST;

typedef struct _node{
	int data;
	NODE* prev;
	NODE* next;
} NODE;

typedef struct _list{
	NODE* head;
} LIST;

void push_back(LIST* list, int data) {
	if (list->head == NULL) {
		NODE* node = (NODE*)malloc(sizeof(NODE));
		node->data = data;
		node->prev = NULL;
		node->next = NULL;
		list->head = node;
		return;
	}

	NODE* node = list->head;
	while (node->next != NULL) {
		node = node->next;
	}
	NODE* new_node = (NODE*)malloc(sizeof(NODE));
	new_node->data = data;
	new_node->prev = node;
	new_node->next = NULL;

	node->next = new_node;

	return;
}

void insert(LIST* list, int data, int n) {
	int i = 0;
	NODE* node = list->head;
	while (node->next != NULL) {
		if (i == n-1) {
			NODE* new_node = (NODE*)malloc(sizeof(NODE));
			new_node->data = data;
			new_node->prev = node;
			new_node->next = node->next;

			node->next = new_node;
			break;
		}
		node = node->next;
		i++;
	}
}

void delete(LIST* list, int n) {
	int i = 0;
	NODE* node = list->head;
	while (node->next != NULL) {
		if (i == n) {
			NODE* prev = node->prev;
			NODE* next = node->next;
			prev->next = next;
			next->prev = prev;
			break;
		}
		node = node->next;
		i++;
	}
}

void print_list(LIST* list) {

	NODE* node = list->head;
	int i = 0;
	while (node != NULL) {
		printf("NODE[%d] data: %d\n", i, node->data);
		node = node->next;
		i++;
	}

	printf("\n");

}

int main(void) {

	LIST list = { NULL };

	push_back(&list, 10);
	push_back(&list, 20);
	push_back(&list, 30);
	push_back(&list, 40);

	print_list(&list);

	insert(&list, 25, 1);

	print_list(&list);

	delete(&list, 3);

	print_list(&list);

	return 0;
}