Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.
For example, given the following binary tree:

1
/   \
2     3
\
5

All root-to-leaf paths are:

["1->2->5", "1->3"]

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<string> result;
vector<string> binaryTreePaths(TreeNode* root) {

if(root == NULL)
return result;
getPath(root,to_string(root->val));
return result;
}

void getPath(TreeNode* root,string path){
if(root->left == NULL && root->right == NULL){
result.push_back(path);
}
if(root->left != NULL)
getPath(root->left,path+"->"+to_string(root->left->val));
if(root->right != NULL)
getPath(root->right,path+"->"+to_string(root->right->val));
}
};