2-binary_tree_insert_right.c

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

/**
 * binary_tree_insert_right - function that inserts a node as
 * the left-child of another node
 *
 * Description: if parent already has a right-child, the new
 * node must take its place and the old right-child must be
 * set as the right-child of the new node.
 *
 * @parent: pointer to the node to insert the right-child in
 * @value: value to store in the new node
 *
 * Return: pointer to the created node, NULL on failure, NULL if parent is NULL
 */
binary_tree_t *binary_tree_insert_right(binary_tree_t *parent, int value)
{
	binary_tree_t *new_node;

	if (parent == NULL)
	{
		return (NULL);
	}

	new_node = binary_tree_node(parent, value);

	if (new_node == NULL)
		return (NULL);

	if (parent->right == NULL)
	{
		parent->right = new_node;
	}
	else
	{
		new_node->right = parent->right;
		parent->right = new_node;
		new_node->right->parent = new_node;
	}

	return (new_node);
}