c++写一个红黑树代码

这是一段红黑树的 C 代码的例子：

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

// 定义红黑树的节点
typedef struct rbtree_node {
  int val;
  char color;
  struct rbtree_node *left, *right, *parent;
} node;

// 定义红黑树
typedef struct rbtree {
  node *root;
} rbtree;

// 创建新节点
node *create_node(int val, char color, node *left, node *right, node *parent) {
  node *new_node = (node*) malloc(sizeof(node));
  new_node->val = val;
  new_node->color = color;
  new_node->left = left;
  new_node->right = right;
  new_node->parent = parent;
  return new_node;
}

// 左旋转
void rotate_left(rbtree *tree, node *x) {
  node *y = x->right;
  x->right = y->left;
  if (y->left != NULL) y->left->parent = x;
  y->parent = x->parent;
  if (x->parent == NULL) {
    tree->root = y;
  } else if (x == x->parent->left) {
    x->parent->left = y;
  } else {
    x->parent->right = y;
  }
  y->left = x;
  x->parent = y;
}

// 右旋转
void rotate_right(rbtree *tree, node *x) {
  node *y = x->left;
  x->left = y->right;
  if (y->right != NULL) y->right->parent = x;
  y->parent = x->parent;
  if (x->parent == NULL) {
    tree->root = y;
  } else if (x == x->parent->right) {
    x->parent->right = y;
  } else {
    x->parent->left = y;
  }
  y->right = x;
  x->parent = y;
}

// 向红黑树中插入新节点
void insert(rbtree *tree, int val) {
  node *new_node = create_node(val, 'R', NULL, NULL, NULL);
  node *temp = tree->root;
  if (temp == NULL) {
    tree->root = new_node;
  } else {
    while (1) {
      if (val < temp->val) {
        if (temp->left == NULL) {
          temp->left = new_node;
          new_node->parent = temp;
          break;
        } else {
          temp = temp->left;
        }
      } else if (val > temp->val)