simple doubly linked list in ansi c

list.c

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

struct node {
  int num;
	struct node *next;
	struct node *prev;
};

struct node *create(int num)
{
	struct node *newnode;

	newnode = (struct node *)malloc(sizeof(struct node));
	if (newnode == NULL) {
		return NULL;
	}

	newnode->num = num;
	newnode->prev = NULL;
	newnode->next = NULL;

	return newnode;
}

void push(struct node **list, int num)
{
	struct node *newnode = create(num);

	if (newnode == NULL) {
		return;
	}

	newnode->num = num;
	newnode->next = *list;

	if (*list != NULL) {
		(*list)->prev = newnode;
	}

	*list = newnode;
}

int pop(struct node **list)
{
	struct node *tmp;
	int val = -1;

	if (*list != NULL) {
		tmp = *list;
		val = (*list)->num;
		*list = (*list)->next;
		if (*list != NULL) {
			(*list)->prev = NULL;
		}
		free(tmp);
	}

	return val;
}

void insertAfter(struct node **list, struct node *current, int num)
{
	struct node *newnode;

	newnode = create(num);

	if (newnode == NULL) {
		return;
	}

	if (*list == NULL) {
		*list = newnode;
	} else {
		newnode->next = current->next;
		newnode->prev = current;
		if (current->next) {
			current->next->prev = newnode;
		}
		current->next = newnode;
	}
}

void deleteCurrent(struct node **list, struct node *current)
{
	if (*list == NULL || current == NULL) {
		return;
	}

	if (*list == current) {
		*list = (*list)->next;
		if (*list != NULL) {
			(*list)->prev = NULL;
		}
	} else {
		current->prev->next = current->next;
		if (current->next != NULL) {
			current->next->prev = current->prev;
		}
	}

	free(current);
}

void deleteAll(struct node *list)
{
	struct node *tmp;

	while (list != NULL) {
		tmp = list;
		list = list->next;
		free(tmp);
	}
}

/*
Callback function that qsort() calls.
*/
int __sortFunc(const void *n1, const void *n2)
{
	struct node **node1 = (struct node **)n1, **node2 = (struct node **)n2;

	if ((*node1)->num < (*node2)->num) {
		return -1;
	}

	if ((*node1)->num > (*node2)->num) {
		return 1;
	}

	return 0;
}

void sort(struct node **list)
{
	int nodeCount = 0, i;
	struct node **tmpList = NULL, *tmp;

	if (*list == NULL) {
		return;
	}

	tmp = *list;
	while (tmp != NULL) {
		nodeCount++;
		tmp = tmp->next;
	}

	/*
		Create a temporary array to hold our list
		Normally, I would save this array for reuse later, and resize it if necessary.
	*/
	tmpList = (struct node **)malloc(sizeof(struct node *) * nodeCount);
	if (tmpList == NULL) {
		return;
	}

	for (i = 0, tmp = *list; i < nodeCount; i++) {
		tmpList[i] = tmp;
		tmp = tmp->next;
	}

	qsort((void *)tmpList, nodeCount, sizeof(struct node *), __sortFunc);

	/* Reconstruct list */
	for (i = 0; i < nodeCount; i++) {
		tmp = tmpList[i];

		if (i == 0) {
			*list = tmpList[0];
			(*list)->prev = NULL;
		} else {
			tmpList[i]->prev = tmpList[i-1];
		}

		if (i + 1 < nodeCount) {
			tmpList[i]->next = tmpList[i+1];
		} else {
			tmpList[i]->next = NULL;
		}
	}

	free(tmpList);
}

void display(struct node *list, struct node *current)
{
	while (list != NULL) {
		printf("%d", list->num);
		if (list == current) {
			printf("(c)");
		}

		if (list->next != NULL) {
			printf(" | ");
		}

		list = list->next;
	}

	printf("\n");
}

void menu(void)
{
	printf("Main Menu\n");
	printf("\t1) Push new value\n");
	printf("\t2) Pop\n");
	printf("\t3) Display all\n");
	printf("\t4) Insert value after current\n");
	printf("\t5) Delete current\n");
	printf("\t6) Move current left\n");
	printf("\t7) Move current right\n");
	printf("\t8) Sort\n");
	printf("\t9) Quit\n");
	printf("\t0) Menu\n");
}

int main(void)
{
	struct node *head = NULL, *current = NULL;
	int input = 0, newNum;

	menu();

	do {
		printf("enter command: ");
		scanf("%d", &input);
		
		switch (input) {
		case 1:
			printf("enter integer: ");
			scanf("%d", &newNum);
			push(&head, newNum);
			if (current == NULL) {
				current = head;
			}
			display(head, current);
			break;
		case 2:
			if (current != NULL && current == head) {
				current = current->next;
			}
			newNum = pop(&head);
			printf("got %d\n", newNum);
			display(head, current);
			break;
		case 3:
			display(head, current);
			break;
		case 4:
			printf("enter integer: ");
			scanf("%d", &newNum);
			insertAfter(&head, current, newNum);
			if (current == NULL) {
				current = head;
			}
			display(head, current);
			break;
		case 5:
			if (current != NULL) {
				deleteCurrent(&head, current);
				current = head;
			}
			display(head, current);
			break;
		case 6:
			if (current && current->prev) {
				current = current->prev;
			}
			display(head, current);
			break;
		case 7:
			if (current && current->next) {
				current = current->next;
			}
			display(head, current);
			break;
		case 8:
			sort(&head);
			display(head, current);
			break;
		case 9:
			deleteAll(head);
			break;
		case 0:
			menu();
			break;
		}

		fflush(stdin);
	} while (input != 9);

	return 0;
}