# Sum of leaf node in BST using recursion in c++ C++ program for Sum of leaf node in BST using recursion. Here mentioned other language solution.

``````// Include header file
#include <iostream>
using namespace std;
// C++ program for
// Sum of all leaf nodes of binary search tree
// Using recusion
class TreeNode
{
public: int data;
TreeNode *left;
TreeNode *right;
TreeNode(int data)
{
this->data = data;
this->left = nullptr;
this->right = nullptr;
}
};
class BinarySearchTree
{
public: TreeNode *root;
BinarySearchTree()
{
this->root = nullptr;
}
// insert a new node
{
// Create a new node
TreeNode *node = new TreeNode(data);
if (this->root == nullptr)
{
// When adds a first node in bst
this->root = node;
}
else
{
TreeNode *find = this->root;
// Add new node to proper position
while (find != nullptr)
{
if (find->data >= data)
{
if (find->left == nullptr)
{
// When left child empty
// So add new node here
find->left = node;
return;
}
else
{
// Otherwise
// Visit left sub-tree
find = find->left;
}
}
else
{
if (find->right == nullptr)
{
// When right child empty
// So add new node here
find->right = node;
return;
}
else
{
// Visit right sub-tree
find = find->right;
}
}
}
}
}
// Sum of leaf nodes
int leafNodeSum(TreeNode *node)
{
if (node != nullptr)
{
if (node->left == nullptr && node->right == nullptr)
{
// When node is leaf node
return node->data;
}
// Visit to left and right subtree
return this->leafNodeSum(node->left) +
this->leafNodeSum(node->right);
}
return 0;
}
};
int main()
{
BinarySearchTree *tree = new BinarySearchTree();
// Add nodes in binary search tree
/*
5
/   \
/     \
3       9
/ \     /  \
2   4   8    10
/
6

*/
// Test
cout << tree->leafNodeSum(tree->root);
return 0;
}``````

Output

``22``

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