#include<stdio.h>
#include<stdlib.h>


typedef struct TreeNode
{
	int data;
	struct TreeNode* left, *right;
}TNode,*BTree;


void PreOrder(BTree T)
{
	if (T != NULL)
	{
		printf("%d ", T->data);
		PreOrder(T->left);
		PreOrder(T->right);
	}
	else
		printf("NULL ");
}

//先释放左右子树，再释放根结点，才能保证完全释放，故一定是后序遍历
void DeleteIt(BTree& T)
{
	if (T != NULL)
	{
		DeleteIt(T->left);
		DeleteIt(T->right);

		printf("删除的是：%d\n ", T->data);

		free(T);
		T = NULL;//这里要置空。
	}
}

//先序遍历到值为x的子树的根结点，将其删除
//否则就继续遍历
//由于对树进行删改，要用引用类型
void PreOrder2(BTree& T, int x)
{
	if (T != NULL)
	{
		if (T->data == x)
			DeleteIt(T);
		else
		{
			PreOrder2(T->left, x);
			PreOrder2(T->right, x);
		}
	}
}

int main()
{
    //首先在这里创建一棵完全二叉树，之前的博客有写，欢迎查看
    
	int x;
	scanf("%d", &x);
	PreOrder2(tree, x);
    //先序遍历，看看是否释放正确
	PreOrder(tree);

	return 0;
}