数据结构树的遍历

#include<iostream>
#include<stdio.h>
#include<conio.h>
using namespace std;
typedef struct btnode
{
int data;
btnode *Lchild,*Rchild;
}*Btnode;
void Creat(Btnode & t)
{
int ch;
cin>>ch;
if(ch==0)
t=NULL;
else
{
btnode *p=new btnode;
p->data=ch;
t=p;
Creat(t->Lchild);
Creat(t->Rchild);
}
}
void Preorder(Btnode & p)
{
if(p!=NULL)
{
cout<<p->data<<"，";
Preorder(p->Lchild);