How to create a binary Tree

#include<bits/stdc++.h>
using namespace std;
#define read() freopen("input.txt", "r", stdin);
#define write() freopen("output.txt", "w", stdout);
#define ll long long int 

struct Node
{
	int data;
    Node *left;
    Node *right;
};

Node *createnode(int item)
{
	Node *temp=new Node();
    if(temp==NULL) {cout<<" Error!! Could not create a new node"<<endl; exit(1);}

   
    temp->data=item;
    temp->left=NULL;
    temp->right=NULL;

    return temp;
}

void add_left_child(Node *node, Node *child)
{
	node->left=child;
}

void add_right_child(Node *node, Node *child)
{
	node->right=child;
}

Node *createtree()
{
	Node *two=createnode(2);
	Node *seven=createnode(7);
	Node *nine=createnode(9);
	add_left_child(two,seven);
	add_right_child(two,nine);

    Node *one=createnode(1);
    Node *six=createnode(6);
    Node *eight=createnode(8);

    add_left_child(seven,one);
    add_right_child(seven,six);
    add_right_child(nine,eight);


    Node *five=createnode(5);
    Node *ten=createnode(10);
    Node *three=createnode(3);
    Node *four=createnode(4);

    add_left_child(six,five);
    add_right_child(six,ten);
    add_left_child(eight,three);
    add_right_child(eight,four);


    return two;

}
int main()
{
	#ifdef asiuzzaman
	read(); write();
	#endif
    Node *root=createtree();
    cout<<root->data<<endl;
    

   
}

            2
          /  \
         7    9
        / \     \
       1   6     8
          / \   / \
          5 10 3   4