1-binary_tree_insert_left.c

#include "binary_trees.h"

/**
 * binary_tree_insert_left - function that inserts a node as the
 *                           left-child of another node
 *
 * @parent: is a pointer to the node to insert the left-child in
 *
 * @value: is the value to store in the new node
 *
 * Return: a pointer to the created node, or NULL on failure or
 *         if parent is NULL
 *
 */
binary_tree_t *binary_tree_insert_left(binary_tree_t *parent, int value)
{
	binary_tree_t *new_node = NULL;

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

	new_node = malloc(sizeof(binary_tree_t));

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

	new_node->n = value;
	new_node->left = NULL;
	new_node->right = NULL;
	new_node->parent = parent;

	if (parent->left != NULL)
	{
		new_node->left = parent->left;
		parent->left->parent = new_node;
		parent->left = new_node;

	}
	else
	{
		parent->left = new_node;
	}

	return (new_node);
}