#include <iostream> #include <queue> #include<string> using namespace std; struct TreeNode { int val; TreeNode* left; TreeNode* right; TreeNode(int x) : val(x), left(NULL), right(NULL) {} }; // 递归实现先序遍历 void preorderTraversal(TreeNode* root) { if (root) { cout << root->val << " "; preorderTraversal(root->left); preorderTraversal(root->right); } } // 非递归实现层次遍历 void levelOrderTraversal(TreeNode* root) { if (!root) { return; } queue<TreeNode*> q; q.push(root); while (!q.empty()) { TreeNode* cur = q.front(); q.pop(); cout << cur->val << " "; if (cur->left) { q.push(cur->left); } if (cur->right) { q.push(cur->right); } } } int main() { // 建立二叉树 TreeNode* root = new TreeNode(65); root->left = new TreeNode(66); root->right = new TreeNode(67); root->left->left = new TreeNode(68); root->left->right = new TreeNode(69); root->left->left->left = new TreeNode(72); root->left->right->right = new TreeNode(73); root->right->left = new TreeNode(70); root->right->right = new TreeNode(71); root->right->left->left = new TreeNode(74); // 先序遍历 cout << "Preorder Traversal: "; preorderTraversal(root); cout << endl; // 层次遍历 cout << "Level Order Traversal: "; levelOrderTraversal(root); cout << endl; return 0; }怎么将代码内节点的数字改成字母

要将节点的数字改成字母，可以将 TreeNode 结构体中的 val 成员变量改为 string 类型，并将节点的值赋为相应的字母。例如，将节点的数字 65 改为字母 A，将节点的数字 66 改为字母 B，以此类推，可以将代码修改如下：

#include <iostream>
#include <queue>
#include <string>
using namespace std;

struct TreeNode {
    string val; // 将节点的值从 int 类型改为 string 类型
    TreeNode* left;
    TreeNode* right;
    TreeNode(string s) : val(s), left(NULL), right(NULL) {} // 将节点的值初始化为字符串类型
};

// 递归实现先序遍历
void preorderTraversal(TreeNode* root) {
    if (root) {
        cout << root->val << " ";
        preorderTraversal(root->left);
        preorderTraversal(root->right);
    }
}

// 非递归实现层次遍历
void levelOrderTraversal(TreeNode* root) {
    if (!root) {
        return;
    }
    queue<TreeNode*> q;
    q.push(root);
    while (!q.empty()) {
        TreeNode* cur = q.front();
        q.pop();
        cout << cur->val << " ";
        if (cur->left) {
            q.push(cur->left);
        }
        if (cur->right) {
            q.push(cur->right);
        }
    }
}

int main() {
    // 建立二叉树
    TreeNode* root = new TreeNode("A"); // 将节点的值从数字改为字母
    root->left = new TreeNode("B");
    root->right = new TreeNode("C");
    root->left->left = new TreeNode("D");
    root->left->right = new TreeNode("E");
    root->left->left->left = new TreeNode("H");
    root->left->right->right = new TreeNode("I");
    root->right->left = new TreeNode("F");
    root->right->right = new TreeNode("G");
    root->right->left->left = new TreeNode("J");

    // 先序遍历
    cout << "Preorder Traversal: ";
    preorderTraversal(root);
    cout << endl;

    // 层次遍历
    cout << "Level Order Traversal: ";
    levelOrderTraversal(root);
    cout << endl;

    return 0;
}

这样就可以将节点的数字改成相应的字母了。