linkedList.c

#include "monty.h"

/**
 * new_head - adds a node to the beginning of doubly linked list
 *
 * @head: pointer to the list
 * @n: integer value to store in the node
 * Return: pointer to the new node;
 */

stack_t *new_head(stack_t **head, const int n)
{
	stack_t *new, *trueHead;

	new = malloc(sizeof(stack_t));
	if (!new)/*malloc failed*/
	{
		free(new);
		dprintf(STDERR_FILENO, "Error: malloc failed\n");
		opCommand[3] = "ERROR";
		return (NULL);
	}
	new->prev = NULL;
	new->n = n;
	if (!*head)/*check if list is empty*/
	{
		new->next = NULL;
		*head = new;
	}
	else/*connects new to begining*/
	{
		trueHead = *head;
		while (trueHead->prev)/*make sure at actual head*/
			trueHead = trueHead->prev;
		new->next = trueHead;
		trueHead->prev = new;
	}
	return (new);
}

/**
 * freeList - frees all nodes in a doubly linked list
 *
 * @head: pointer to the list
 */

void freeList(stack_t *head)
{
	stack_t *hide, *seek;

	if (!head)/*there is no list*/
		return;
	seek = head;
	while (seek->prev)/*find true head*/
		seek = seek->prev;
	while (seek)/*free each node*/
	{
		hide = seek;
		seek = seek->next;
		free(hide);
	}
}

/**
 * new_tail - adds a node to the end of a doubly linked list
 * @head: pointer to the list
 * @n: integer value to store in the node
 *
 * Return: pointer to new node, NULL on failure
 */

stack_t *new_tail(stack_t **head, const int n)
{
	stack_t *new, *tail;

	new = malloc(sizeof(stack_t));
	if (!new)/*malloc failed*/
	{
		dprintf(STDERR_FILENO, "Error: malloc failed\n");
		free(new);
		opCommand[3] = "ERROR";
		return (NULL);
	}
	new->n = n;
	new->next = NULL;
	if (!*head)/*no current nodes*/
	{
		new->prev = NULL;
		*head = new;
	}
	else/*connect to end of list*/
	{
		tail = *head;
		while (tail->next)/*find the tail*/
			tail = tail->next;
		tail->next = new;
		new->prev = tail;
	}
	return (new);
}