二叉树的基本操作的源代码

下面是二叉树的基本操作的源代码：

#include <iostream>
#include <queue>

using namespace std;

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

// 二叉树的先序遍历（递归实现）
void PreorderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    cout << root->val << " ";
    PreorderTraversal(root->left);
    PreorderTraversal(root->right);
}

// 二叉树的中序遍历（递归实现）
void InorderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    InorderTraversal(root->left);
    cout << root->val << " ";
    InorderTraversal(root->right);
}

// 二叉树的后序遍历（递归实现）
void PostorderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    PostorderTraversal(root->left);
    PostorderTraversal(root->right);
    cout << root->val << " ";
}

// 二叉树的层序遍历（非递归实现）
void LevelorderTraversal(TreeNode* root) {
    if (root == NULL) {
        return;
    }
    queue<TreeNode*> q;
    q.push(root);
    while (!q.empty()) {
        TreeNode* node = q.front();
        cout << node->val << " ";
        q.pop();
        if (node->left != NULL) {
            q.push(node->left);
        }
        if (node->right != NULL) {
            q.push(node->right);
        }
    }
}

// 二叉树的查找
TreeNode* Search(TreeNode* root, int val) {
    if (root == NULL) {
        return NULL;
    }
    if (root->val == val) {
        return root;
    }
    TreeNode* left = Search(root->left, val);
    if (left != NULL) {
        return left;
    }
    TreeNode* right = Search(root->right, val);
    if (right != NULL) {
        return right;
    }
    return NULL;
}

// 二叉树的插入
void Insert(TreeNode* root, int val) {
    if (root == NULL) {
        return;
    }
    if (root->left == NULL) {
        root->left = new TreeNode(val);
        return;
    }
    if (root->right == NULL) {
        root->right = new TreeNode(val);
        return;
    }
    Insert(root->left, val);
    Insert(root->right, val);
}

// 二叉树的删除
void Delete(TreeNode* root, int val) {
    if (root == NULL) {
        return;
    }
    if (root->left != NULL && root->left->val == val) {
        TreeNode* temp = root->left;
        root->left = NULL;
        delete temp;
        return;
    }
    if (root->right != NULL && root->right->val == val) {
        TreeNode* temp = root->right;
        root->right = NULL;
        delete temp;
        return;
    }
    Delete(root->left, val);
    Delete(root->right, val);
}

int main() {
    // 创建二叉树
    TreeNode* root = new TreeNode(1);
    root->left = new TreeNode(2);
    root->right = new TreeNode(3);
    root->left->left = new TreeNode(4);
    root->left->right = new TreeNode(5);
    root->right->left = new TreeNode(6);
    root->right->right = new TreeNode(7);

    // 二叉树的遍历
    cout << "PreorderTraversal: ";
    PreorderTraversal(root);
    cout << endl;

    cout << "InorderTraversal: ";
    InorderTraversal(root);
    cout << endl;

    cout << "PostorderTraversal: ";
    PostorderTraversal(root);
    cout << endl;

    cout << "LevelorderTraversal: ";
    LevelorderTraversal(root);
    cout << endl;

    // 二叉树的查找
    cout << "Search: " << Search(root, 5)->val << endl;

    // 二叉树的插入
    Insert(root, 8);
    cout << "LevelorderTraversal: ";
    LevelorderTraversal(root);
    cout << endl;

    // 二叉树的删除
    Delete(root, 5);
    cout << "LevelorderTraversal: ";
    LevelorderTraversal(root);
    cout << endl;

    return 0;
}