C++類實現二叉樹的構建和遍歷

#include
#include 
#include 
using namespace std;

/*二叉樹的結構體*/
typedef struct BTree
{
	int val;
	struct BTree *left,*right;	
}BTree;

/*二叉樹的類，包含著操作二叉樹的各種方法*/ 
class Tree
{
	public:
	BTree *create_node(int level,string pos);
	void PreOrder(BTree *t);  //先序遍歷 
	void InOrder(BTree *t);  //中序遍歷 
	void PostOrder(BTree *t);  //後序遍歷 
	
	BTree *root;	
};

/*用先序遍歷的方法遞歸構造一課二叉樹*/ 
BTree* Tree::create_node(int level,string pos)
{
	int data;
	BTree *node = new BTree;
	
	cout<<"please enter data:level "<