p.cpp

#include <bits/stdc++.h>
using namespace std;
class Node
{
public:
	int data;
	Node *left;
	Node *right;
	Node(int value)
	{
		data = value;
		left = nullptr;
		right = nullptr;
	}
};

void preorder(Node *root)
{
	if (root)
	{
		cout << root->data << " ";
		preorder(root->left);
		preorder(root->right);
	}
}

void it(Node *root)
{
	if (!root)
		return;
	stack<Node *> ans;
	while (root or !ans.empty())
	{
		while (root)
		{
			cout << root->data << " ";
			ans.push(root);
			root = root->left;
		}
		root = ans.top();
		ans.pop();
		root = root->right;
	}
}
void rightview(Node *root)
{
	vector<int> view;
	if (!root)
		return;
	vector<int> count;
	queue<Node *> s;
	s.push(root);
	s.push(nullptr);
	view.push_back(root->data);
	while (!s.empty())
	{
		Node *cuur = s.front();
		s.pop();
		if (!cuur)
		{
			if (count.size())
				view.push_back(count.back());
			s.push(nullptr);
			count.clear();
			if (s.empty())
				break;
			continue;
		}
		if (cuur->left)
		{
			s.push(cuur->left);
			count.push_back(cuur->left->data);
		}
		if (cuur->right)
		{
			s.push(cuur->right);
			count.push_back(cuur->right->data);
		}
	}
	for (auto i : view)
		cout << i << " ";
}
void leveorder(Node* root){
	queue<Node*>a;

a.push(root);
while(!a.empty()){
Node*temp = a.front();
a.pop();
cout<<temp->data<<" ";
if(temp->left)a.push(temp->left);
if(temp->right)a.push(temp->right);
}

}
int main()
{
	Node *d = new Node(1);
	d->left = new Node(2);
	d->right = new Node(3);
	d->left->right = new Node(4);
	d->left->left = new Node(5);
	// preorder(d);
	cout << '\n';
	// it(d);
	// rightview(d);
	leveorder(d);
	return 0;
}