B_tree_nodes_at_k_distance.cpp

#include<bits/stdc++.h>  
  
using namespace std; 
  
/* A binary tree node has data, 
pointer to left child and 
a pointer to right child */
class node  
{  
    public: 
    int data;  
    node* left;  
    node* right;  
      
    /* Constructor that allocates a new node with the  
    given data and NULL left and right pointers. */
    node(int data) 
    { 
        this->data = data; 
        this->left = NULL; 
        this->right = NULL; 
    } 
};  
  
void printKDistance(node *root , int k)  
{  
     //Practise Yourself : Write your code Here  
     if(root==NULL){
         return;
     }
     if(k==0){
         cout<<root->data<<" ";
         return;
     }
     printKDistance(root->left,k-1);
     printKDistance(root->right,k-1);
}  
  
  

int main()  
{  
  
  
    node *root = new node(1);  
    root->left = new node(2);  
    root->right = new node(3);  
    root->left->left = new node(4);  
    root->left->right = new node(5);  
    root->right->left = new node(8);  
      
    printKDistance(root, 2);  
    return 0;  
}  

/* Try more Inputs

/* Constructed binary tree is           
             1  
            / \  
           2   3  
          / \ /  
         4  5 8  
    */
/*Case 1:
Main tree = new Main(); 
tree.root = new Node(1);  
tree.root.left = new Node(2);  
tree.root.right = new Node(3);  
tree.root.left.left = new Node(4);  
tree.root.left.right = new Node(5);  
tree.root.right.left = new Node(8); 
tree.printLeftView(tree.root,2)
expected = [4,5,8]*/

//Case2: 
/* Constructed binary tree is           
             10  
            / \  
           12  3  
           \  /  
            4 5  
                \
                 6
*/
/*BinaryTree root = newNode(10);
root.left = newNode(12);
root.right = newNode(3);
root.left.right = newNode(4);
root.right.left = newNode(5);
root.right.left.right = newNode(6);
tree.printLeftView(root,2)
expected = [4,5]
*/