二叉树层次顺序插入c++

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

void insert(TreeNode* root, int value) {
    if (root == nullptr) {
        root = new TreeNode(value);
        return;
    }

    queue<TreeNode*> q;
    q.push(root);

    while (!q.empty()) {
        TreeNode* node = q.front();
        q.pop();

        if (node->left == nullptr) {
            node->left = new TreeNode(value);
            return;
        } else {
            q.push(node->left);
        }

        if (node->right == nullptr) {
            node->right = new TreeNode(value);
            return;
        } else {
            q.push(node->right);
        }
    }
}

int main() {
    TreeNode* root = new TreeNode(1);
    insert(root, 2);
    insert(root, 3);
    insert(root, 4);
    insert(root, 5);

    // 输出二叉树的层次遍历结果
    queue<TreeNode*> q;
    q.push(root);

    while (!q.empty()) {
        TreeNode* node = q.front();
        q.pop();

        cout << node->val << " ";

        if (node->left != nullptr) {
            q.push(node->left);
        }

        if (node->right != nullptr) {
            q.push(node->right);
        }
    }

    return 0;
}