二叉树的基本操作

include <stdio.h>

include <stdlib.h>

// 定义二叉树的节点结构
typedef struct TreeNode {
int data;
struct TreeNode *left;
struct TreeNode *right;
} TreeNode;

// 创建新节点
TreeNode* createNode(int data) {
TreeNode newNode = (TreeNode)malloc(sizeof(TreeNode));
newNode->data = data;
newNode->left = newNode->right = NULL;
return newNode;
}

// 前序遍历
void preOrder(TreeNode *root) {
if (root) {
printf("%d ", root->data);
preOrder(root->left);
preOrder(root->right);
}
}

// 中序遍历
void inOrder(TreeNode *root) {
if (root) {
inOrder(root->left);
printf("%d ", root->data);
inOrder(root->right);
}
}

// 后序遍历
void postOrder(TreeNode *root) {
if (root) {
postOrder(root->left);
postOrder(root->right);
printf("%d ", root->data);
}
}

// 释放二叉树的内存
void freeTree(TreeNode *root) {
if (root) {
freeTree(root->left);
freeTree(root->right);
free(root);
}
}