#include<bits/stdc++.h>
using namespace std;
struct node
{
    int data;
    node *left, *right;
    node(int data)
    {
        this -> data = data;
        this -> left = NULL;
        this -> right = NULL;
    }
};
struct BST
{
    node *root = NULL;
    node* insertHelper(node *cur, node *temp)
    {
        if(!cur)
            return temp;
        if(cur -> data < temp -> data)
            cur -> right = insertHelper(cur -> right, temp);
        else cur -> left = insertHelper(cur -> left, temp);
        return cur;
    }
    void insert(int data)
    {
        node *temp = new node(data);
        if(!root) root = temp;
        else root = insertHelper(root, temp);
    }
    void printHelper(node *cur)
    {
        if(!cur)
            return;
        printf("%d -> ", cur -> data);
        printHelper(cur -> left);
        printHelper(cur -> right);
    }
    void preOrder()
    {
        printHelper(root);
        printf("\n");
    }
};
int main()
{
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    BST a;
    a.insert(10);
    a.insert(20);
    a.insert(100);
    a.insert(50);
    a.insert(80);
    a.insert(75);
    a.insert(99);
    a.preOrder();
}