BST.cpp

/// Program for creating a binary tree using nodes and preorder traversal - left root right


#include<bits/stdc++.h>
using namespace std;

struct Node{
    int value;
    struct Node * left,* right,* root;
};

struct Node * createNode(int val){
    
    struct Node * newNode= new Node;
    newNode->value=val;
    newNode->left=newNode->right=NULL;
    newNode->root=NULL;
    return newNode;
}


///To Print BST
void inOrderTraversal(Node *head){

    if(head==NULL) return;

    inOrderTraversal(head->left);

    cout<<head->value<<" ";

    inOrderTraversal(head->right);

}


struct Node * insertNode(Node *head,int val){
    if(head==NULL) return createNode(val);

    if(head->value > val){
        Node * lchild=insertNode(head->left,val);
        head->left=lchild;
        lchild->root=head;
    }
    else if(head->value<val){
        Node * rchild=insertNode(head->right,val);
        head->right=rchild;
        rchild->root=head;
    }
    return head;
}

// Driver Program to test above functions
int main()
{
    /* Let us create following BST
              50
           /     \
          30      70
         /  \    /  \
       20   40  60   80 */
    struct Node *root = NULL;
    root = insertNode(root, 50);
    insertNode(root, 30);   
    insertNode(root, 20);
    insertNode(root, 40);
    insertNode(root, 70);
    insertNode(root, 60);
    insertNode(root, 80);
 
    // print inorder traversal of the BST
    inOrderTraversal(root);
 
    return 0;
}