#include<iostream>
#include<stack>
#include<vector>
using namespace std;
struct node
{
int val;
node *left,*right;
node(int _val):val(_val),left(NULL),right(NULL){
}
};
struct bignode
{
bool isfirst;
node* pnode;
};
void postorder(node* root)
{
stack<bignode*> sta;
node *p=root;
while(p!=NULL||!sta.empty())
{
while(p)
{
bignode *tmp=new bignode();
tmp->isfirst=true;
tmp->pnode=p;
sta.push(tmp);
p=p->left;
}
if(!sta.empty())
{
bignode *tmp=sta.top();
sta.pop();
if(tmp->isfirst)
{
tmp->isfirst=false;
sta.push(tmp);
p=tmp->pnode->right;
}
else
{
cout<<tmp->pnode->val<<" ";
p=NULL;
}
}
}
}
void preorder(node* root)
{
stack<node*> sta;
node* p=root;
while(p!=NULL||!sta.empty())
{
while(p){
cout<<p->val<<" ";
sta.push(p);
p=p->left;
}
if(!sta.empty())
{
node * tmp=sta.top();
sta.pop();
p=tmp->right;
}
}
}
void inorder(node* root)
{
stack<node*> sta;
node* p=root;
while(p!=NULL||!sta.empty())
{
while(p){
sta.push(p);
p=p->left;
}
if(!sta.empty())
{
node * tmp=sta.top();
cout<<tmp->val<<" ";
sta.pop();
p=tmp->right;
}
}
}
int main()
{
node n1(1),n2(2),n3(3),n4(4),n5(5),n6(6);
n1.left=&n2;
n1.right=&n3;
n2.left=&n4;
n2.right=&n5;
n3.left=&n6;
inorder(&n1);
return 1;
}