二叉排序树转换为有序的双向链表c语言

二叉排序树转换为有序的双向链表的C语言实现：

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

// 定义二叉树节点结构体
typedef struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
} TreeNode;

// 定义双向链表节点结构体
typedef struct ListNode {
    int val;
    struct ListNode *prev;
    struct ListNode *next;
} ListNode;

// 将二叉排序树转换为有序的双向链表
ListNode* treeToList(TreeNode* root) {
    if (root == NULL) {
        return NULL;
    }
    // 将左子树转换为有序的双向链表
    ListNode *leftList = treeToList(root->left);
    // 将右子树转换为有序的双向链表
    ListNode *rightList = treeToList(root->right);
    // 创建当前节点的双向链表节点
    ListNode *curNode = (ListNode*)malloc(sizeof(ListNode));
    curNode->val = root->val;
    curNode->prev = NULL;
    curNode->next = NULL;
    // 将左子树的双向链表和当前节点连接起来
    if (leftList != NULL) {
        ListNode *leftTail = leftList;
        while (leftTail->next != NULL) {
            leftTail = leftTail->next;
        }
        leftTail->next = curNode;
        curNode->prev = leftTail;
    } else {
        leftList = curNode;
    }
    // 将右子树的双向链表和当前节点连接起来
    if (rightList != NULL) {
        rightList->prev = curNode;
        curNode->next = rightList;
    }
    return leftList;
}

// 创建二叉树节点
TreeNode* createNode(int val) {
    TreeNode *node = (TreeNode*)malloc(sizeof(TreeNode));
    node->val = val;
    node->left = NULL;
    node->right = NULL;
    return node;
}

// 插入节点到二叉排序树中
TreeNode* insertNode(TreeNode *root, int val) {
    if (root == NULL) {
        return createNode(val);
    }
    if (val < root->val) {
        root->left = insertNode(root->left, val);
    } else {
        root->right = insertNode(root->right, val);
    }
    return root;
}

// 中序遍历二叉树
void inorderTraversal(TreeNode *root) {
    if (root == NULL) {
        return;
    }
    inorderTraversal(root->left);
    printf("%d ", root->val);
    inorderTraversal(root->right);
}

// 打印双向链表
void printList(ListNode *head) {
    ListNode *curNode = head;
    while (curNode != NULL) {
        printf("%d ", curNode->val);
        curNode = curNode->next;
    }
    printf("\n");
}

int main() {
    // 创建二叉排序树
    TreeNode *root = NULL;
    root = insertNode(root, 5);
    insertNode(root, 3);
    insertNode(root, 7);
    insertNode(root, 2);
    insertNode(root, 4);
    insertNode(root, 6);
    insertNode(root, 8);
    // 中序遍历二叉树
    printf("Inorder traversal of binary search tree:\n");
    inorderTraversal(root);
    printf("\n");
    // 将二叉排序树转换为有序的双向链表
    ListNode *head = treeToList(root);
    // 打印双向链表
    printf("Doubly linked list:\n");
    printList(head);
    return ;
}