Leetcode Binary Tree Inorder Traversal

/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector inorderTraversal(TreeNode *root) {
TreeNode *current = root;
stack<TreeNode *> temp;
vector result;
while(1){
while(current){
temp.push(current);
current = current->left;
}

            if(!temp.empty()){
                current = temp.top();
                temp.pop();
                result.push_back(current->val);
                current = current->right;
            }
            else
                break;
        }
        return result;

    }
};