//tree.cpp
#include<iostream.h>
#include "tree.h"
 node::node(int x)
{
 data=x;
}
 node::~node()
{
 cout<<"二叉樹的結點被析構"<<endl;
}
 tree::tree(void)
{
 root=0;
}
 tree::~tree()
{
 free_t(root);
 cout<<"二叉樹被析構"<<endl;
}
 void tree::free_t(node *r)
{
 if(r!=0)
 {
  free_t(r->left);
  free_t(r->right);
  delete r;
 } 
}
 node* tree::get_r()
{
 return(root);
}
 void tree::build_t(int d)
{
 node *p,*q;
 if(root==0)//空樹
 {
  root=new node(d);
  root->left=0;
  root->right=0;
 }
 else
 {
  p=root;
  while(p!=0)
  {
   q=p;
   if(d<p->data)
	p=p->left;
   else
	p=p->right;
  }
  node *newp=new node(d);
  newp->left=0;
  newp->right=0;
  if(d<q->data)
   q->left=newp;
  else
   q->right=newp;
 }
}
 void tree::preorder(node *r)//前序遍歷
{
 if(r!=0)
 {
  cout<<r->data<<" ";
  preorder(r->left);
  preorder(r->right);
 }
}
 void tree::inorder(node *r)//中序遍歷
{
 if(r!=0)
 {
  inorder(r->left);
  cout<<r->data<<" ";
  inorder(r->right);
 }
}
 void tree::postorder(node *r)//后序遍歷
{
 if(r!=0)
 {
  postorder(r->left);
  postorder(r->right);
  cout<<r->data<<" ";
 }
}