track_stack.c

#include "binary_trees.h"

/**
 * stack_create - creates a stack by repurposing binary nodes
 *
 * Return: pointer to the top of the stack
 */
binary_tree_t *stack_create(void)
{
	binary_tree_t *top;

	top = malloc(sizeof(binary_tree_t));
	if (top == NULL)
		exit(1);

	top->n = 0;
	top->parent = NULL;
	top->left = NULL;
	top->right = NULL;

	return (top);
}

/**
 * stack_pop - removes top of the stack
 * @top: top of the stack
 *
 * Return: pointer to binary node
 */
binary_tree_t *stack_pop(binary_tree_t **top)
{
	binary_tree_t *current, *old_top;

	current = (*top)->parent;

	old_top = *top;
	*top = (*top)->right;
	if (*top != NULL)
		(*top)->left = NULL;
	free(old_top);

	return (current);
}

/**
 * stack_push - reimplements binary_tree_t as a stack
 * @top: top of the stack
 * @current: node to push to the top
 *
 * Return: void
 */
void stack_push(binary_tree_t **top, binary_tree_t *current)
{
	binary_tree_t *new;

	new = malloc(sizeof(binary_tree_t));
	if (new == NULL)
		exit(1);

	new->n = 0;
	new->parent = current;
	new->left = NULL;
	new->right = *top;
	(*top)->left = new;
	*top = new;
}