Doubly linked list implemented in C without any global variables.

doublyLinkedList.c

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

Node* createnode(){
	Node* node = malloc(sizeof(*node));
	return node;
}

void addNode(Node** head, int info){
	Node* node = createnode();
	node->key = info;
	node->next = NULL;

	if(*head == NULL){
		*head = createnode();
		node->prev = NULL;
	}
	else{
		node->prev = *head;
		(*head)->next = node;
	}

	*head = node;
}

void deleteHeadNode(Node** head){
	Node* tmp = *head;
	(*head)->prev->next = NULL;
	(*head) = (*head)->prev;
	tmp->prev = NULL;
	free(tmp);printf("Head Node deleted.\n");
}

void insertNodeBetween(Node** head, int info, int position){
	Node* tmp = *head;
	int counter = 1;
	while(tmp->prev != NULL){
		tmp = tmp->prev;
		counter++;
	}
	if(position > counter){
		printf("Position exceeds the number of elements. Cannot insert element.\n");		
		return ;
	}
	else{
		while(--position){
			tmp = tmp->next;
		}
		Node* new = malloc(sizeof(*new));
		new->key = info;
		new->next = tmp->next;
		new->prev = tmp;
		tmp->next->prev = new;
		tmp->next = new;
	}
}

void addNodeTail(Node** head, int data){
	Node* tmp = *head;
	while(tmp->prev != NULL){
		tmp = tmp->prev;
	}
	Node* new = malloc(sizeof(*new));
	new->key = data;
	new->prev = NULL;
	new->next = tmp;
	tmp->prev = new;
}

void deleteNode(Node** head, int position){
	Node* tmp = *head;
	int counter = 1;
	int n = position;
	while(tmp->prev != NULL){
		tmp = tmp->prev;
		counter++;
	}
	if(position > counter){
		printf("Position exceeds the number of elements. Unable to delete.\n");
		return ;
		
	}
	else if(position == 1){
		tmp->next->prev = NULL;
		tmp->next = NULL;
		free(tmp);
		printf("Deleted tail node\n");

	}
	else{
		while(--n){
			tmp = tmp->next;
		}
		tmp->prev->next = tmp->next;
		tmp->next->prev = tmp->prev;
		tmp->next = NULL;
		tmp->prev = NULL;
		free(tmp);printf("Element deleted.\n");
	}
}

void getNode(Node** head, int position){
	Node* tmp = *head;
	int counter = 1;
	int n = position;
	while(tmp->prev != NULL){
		counter++;
		tmp = tmp->prev;
	}
	if(position > counter){
		printf("Position exceeds the number of elements. Cannot fetch node.\n");
		return ;
		
	}
	else{
		while(--n){
			//printf("n = %d ", n);
			tmp = tmp->next;
		}
		printf("Node at %d is %d\n",position, tmp->key);
	}
}

void searchNode(Node** head, int searchfor){
	Node* tmp = *head;
	int searchswitch = 0;
	while(tmp != NULL){
		if(tmp->key == searchfor){
			printf("Element %d found!!\n",searchfor);
			searchswitch = 1;
		}
		tmp = tmp->prev;
	}
	if(!searchswitch){
		printf("Element %d NOT found.\n",searchfor);
	}
}

void printRev(Node* head){
	Node* tmp = head;
	while(tmp != NULL){
		printf("<-[%d]",(tmp)->key);
		tmp = (tmp)->prev;
	}
	printf("\n");
}

void printFwd(Node* head){
	Node* tmp = head;
	while(tmp->prev != NULL){
		tmp = (tmp)->prev;
	}
	while(tmp != NULL){
		printf("[%d]->", tmp->key);
		tmp = tmp->next;
	}
	printf("\n");
}

doublyLinkedList.h

#ifndef DOUBLYLINKEDLIST_H
#define DOUBLYLINKEDLIST_H

typedef struct node {
		int key;
		struct node* next;
		struct node* prev;
} Node;

Node* createnode();

void addNode(Node** head, int info);

void deleteHeadNode(Node** head);

void deleteNode(Node** head, int position);

void insertNodeBetween(Node** head, int info, int position);

void addNodeTail(Node** head, int data);

void getNode(Node** head, int position);

void searchNode(Node** head, int searchfor);

void printRev(Node* head);
void printFwd(Node* head);

#endif

main.c

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

int main(){
	Node* head = NULL;
	addNode(&head, 21);
	addNode(&head, 33);
	addNode(&head, 41);
	addNode(&head, 56);
	addNode(&head, 78);
	addNode(&head, 99);
	addNode(&head, 700);
	printFwd(head);
	deleteHeadNode(&head);
	printFwd(head);
	insertNodeBetween(&head,889,3);
	insertNodeBetween(&head,92,3);
	insertNodeBetween(&head,770,4);
	insertNodeBetween(&head,770,64);
	printFwd(head);
	searchNode(&head, 78);
	searchNode(&head, 99999);
	addNodeTail(&head, 111111);
	addNodeTail(&head, 3331);
	printFwd(head);
	deleteNode(&head, 1);
	deleteNode(&head, 7);
	deleteNode(&head, 97);
	insertNodeBetween(&head, 101010, 7);
	getNode(&head, 5);
	getNode(&head, 1);
	getNode(&head, 12);
	printFwd(head);
	printRev(head);
	return 0;
}