二叉树实现

#include <iostream>
using namespace std;
class Node
{
public:
	int data;
	Node * leftChild;
	Node * rightChild;
};
class BiTree
{
private:
	void insert(Node *&root,Node *&d)
	{
		if(root == NULL) 
			root = d;
		else 
			if(d->data < root->data) 
			insert(root->leftChild,d);
		else
			insert(root->rightChild,d); 
	}
	void inorder(Node *p);
	void preorder(Node *p);
	void postorder(Node *p);

public:
	Node * root;
	BiTree();
	~BiTree();
	void add(int value)//add element to tree
	{
		Node *n = new Node;
		n->data = value;
		n->leftChild = NULL;
		n->rightChild = NULL;
		insert(root,n);
	}
	void inorderTravel();
	void preorderTravel();
	void postorderTravel();
};

BiTree::BiTree()
{
	root = NULL;
}
BiTree::~BiTree()
{

}
//中序遍历
void BiTree::inorderTravel()
{
	inorder (root);
}
//前序遍历
void BiTree::preorderTravel ()
{
	preorder(root);
}

//后序遍历
void BiTree::postorderTravel ()
{
	postorder(root);
}


void BiTree::inorder (Node *p)
{
	if(p!=NULL)
	{
		inorder(p->leftChild );
		cout<<p->data <<" ";
		inorder(p->rightChild);
	}
}
void BiTree::preorder(Node *p)
{
	if(p!=NULL)
	{
		cout<<p->data <<" ";
		preorder(p->leftChild );  
		preorder(p->rightChild );
	}
}

void BiTree::postorder (Node *p)
{
	if(p!=NULL)
	{
		postorder(p->leftChild);
		postorder(p->rightChild);
		cout<<p->data <<" ";
	}
}

int main()
{
   BiTree bt;
   int i = 10;
   while (i--)
    bt.add(i);
   bt.inorderTravel();
   cout << endl;
   bt.preorderTravel();
   cout << endl;
   bt.postorderTravel();
   cout << endl;
}