输出正常最后显示已停止工作

#include <iostream>
using namespace std;
/*
typedef struct TreeNode
{
int data;
TreeNode * left;
TreeNode * right;
TreeNode * parent;
}TreeNode;


void pre_order(TreeNode* Node)
{
if(Node != NULL)
{
cout<<Node->data;
pre_order(Node->left);
pre_order(Node->right);
}
}*///20


typedef struct Node
{
int data;
// Tree left;
// Tree right;
struct Node *left;
struct Node *right;
}*Tree;


void create_tree(Tree &T)
{
int data;
cin>>data;
if(data==0)
{
cout<<"The tree is null!"<<endl;
}
else
{
T = (Tree)malloc(sizeof(Node));
T->data = data;
create_tree(T->left);
create_tree(T->right);
}
}


void visit(Tree T)
{
if(T->data!=0)
{
cout<<T->data;
}
}


void pre_order(Tree T)
{
// if(T->data!=0)
if(T!=NULL)
{
visit(T);
pre_order(T->left);
pre_order(T->right);
}
}


void in_order(Tree T)
{
if(T!=NULL)
{
in_order(T->left);
visit(T);
in_order(T->right);
}
}


void post_order(Tree T)
{
if(T!=NULL)
{
post_order(T->left);
post_order(T->right);
visit(T);
}
}


int main()
{
// TreeNode *first = (TreeNode*)malloc(sizeof(TreeNode));
Tree T;
create_tree(T);//90
pre_order(T);



return 0;
}