leetcode 129. Sum Root to Leaf Numbers

class Solution {public:int sumNumbers(TreeNode* root){if (root == nullptr){return sum;}process(root, 0);return sum;}private:int sum{};void process(TreeNode* root, int temp){temp = temp * 10 + root->val;if (root->left == nullptr && root->right == nullptr){sum += temp;return;}if (root->left){process(root->left, temp);}if (root->right){process(root->right, temp);}}};