代码生成，用C++编写遍历二叉树

好的，您希望我为您生成遍历二叉树的 C 代码。以下是示例代码：

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

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};

void traverse(struct TreeNode* root) {
    if (root != NULL) {
        traverse(root->left);
        printf("%d ", root->val);
        traverse(root->right);
    }
}

int main() {
    // create a binary tree
    struct TreeNode* root = (struct TreeNode*) malloc(sizeof(struct TreeNode));
    root->val = 1;
    root->left = (struct TreeNode*) malloc(sizeof(struct TreeNode));
    root->left->val = 2;
    root->left->left = NULL;
    root->left->right = NULL;
    root->right = (struct TreeNode*) malloc(sizeof(struct TreeNode));
    root->right->val = 3;
    root->right->left = (struct TreeNode*) malloc(sizeof(struct TreeNode));
    root->right->left->val = 4;
    root->right->left->left = NULL;
    root->right->left->right = NULL;
    root->right->right = NULL;

    // traverse the tree
    printf("In-order traversal: ");
    traverse(root);

    return 0;
}

这是一种简单的递归方式，通过先递归访问左子树，再访问当前节点，最后递归访问右子树，实现二叉树的中序遍历。您可以根据需求修改这段代码。