C++ program that uses non-recursive functions to traverse a binary tree in In-order

#include<iostream>
#include<conio.h>
#include<stdlib.h>
using namespace std;
class node
{
public:
class node *left;
class node *right;
int data;
};
 
class tree: public node
{
public:
int stk[50],top;
node *root;
tree()
{
root=NULL;
top=0;
}
void insert(int ch)
{
	node *temp,*temp1;
	if(root== NULL)
	{
		root=new node;
		root->data=ch;
		root->left=NULL;
		root->right=NULL;
		return;
	}
	temp1=new node;
	temp1->data=ch;
	temp1->right=temp1->left=NULL;
	temp=search(root,ch);
	if(temp->data>ch)
		temp->left=temp1;
	else
		temp->right=temp1;
 
}
 
node *search(node *temp,int ch)
{
	if(root== NULL)
	{
		cout <<"no node present";
		return NULL;
	}
	if(temp->left==NULL && temp->right== NULL)
		return temp;
 
	if(temp->data>ch)
	     {  if(temp->left==NULL) return temp;
		search(temp->left,ch);}
	else
	      { if(temp->right==NULL) return temp;
	      search(temp->right,ch);
 
}              }
 
void display(node *temp)
{
	if(temp==NULL)
	    return ;
	display(temp->left); 
	cout<<temp->data;
	display(temp->right);
}
void inorder( node *root)
{
	node *p;
	p=root;
	top=0;
	do
	{
		while(p!=NULL)
		{
			stk[top]=p->data;
			top++;
			p=p->left;
		}
		if(top>0)
		{
			p=pop(root);
			cout << p->data;
			p=p->right;
		}
	}while(top!=0 || p!=NULL);
}
 
 
node * pop(node *p)
{
	int ch;
	ch=stk[top-1];
	if(p->data==ch)
	{
		top--;
		return p;
	}
	if(p->data>ch)
		pop(p->left);
	else
		pop(p->right);
}
};
 
main()
{
	tree t1;
	int ch,n,i;
	while(1)
	{
		cout <<"\n1.INSERT\n2.DISPLAY 3.INORDER TRAVERSE\n4.EXIT\nEnter your choice:";
		cin >> ch;
		switch(ch)
		{
		case 1:   cout <<"enter no of elements to insert:";
			  cin >> n;
			  for(i=1;i<=n;i++)
			  {  cin >> ch;
			     t1.insert(ch);
			  }
			   break;
		case 2:   t1.display(t1.root);break;
		case 3:   t1.inorder(t1.root); break;
		case 4:   exit(1);
		}
	}
}