關於二叉樹的前序遍歷、中序遍歷、刪除元素、插入元素

#include<iostream>
#include<cstdio>
#include<queue>
#include<cmath>
#include<cstdlib>
using namespace std;
struct node
{
	int data;
	struct node*left;
	struct node*right;
};
node tree;
struct node * create(int t)
{
	node* tmp=new node;
	tmp->data=t;
	tmp->left=tmp->right=NULL;
	return tmp;
}
struct node * insert(struct node *root,int t)
{
	if(root==NULL)root=create(t);
	if(root->data>t)root->left=insert(root->left,t);
	else if(root->data<t)root->right=insert(root->right,t);
	return root;
}
void preorder(struct node* root)
{
	if(!root)return;
	printf("%d ",root->data);
	preorder(root->left);
	preorder(root->right);
} 
void levelorder(struct node *root)
{
	if(!root)return;
	queue<struct node*>q;
	q.push(root);
	while(!q.empty())
	{
		struct node *tmp=q.front();
		q.pop();
		printf("%d ",tmp->data);
		if(tmp->left)q.push(tmp->left);
		if(tmp->right)q.push(tmp->right);
	}
}
int getheight(struct node* root)
{
	if(!root)return 0;
	int h1=getheight(root->left);
	int h2=getheight(root->right);
	return 1+max(h1,h2);
}
struct node* Findmin(struct node* root)
{
	if(!root)return NULL;
	struct node* tmp=root;
	while(tmp->left)tmp=tmp->left;
	return tmp; 
}
struct node * Delete(struct node *root,int x)
{
	if(!root)return NULL;
	if(x<root->data)root->left=Delete(root->left,x);
	else if(x>root->data)root->right=Delete(root->right,x);
	else
	{
		struct node *tmp=root;
		if(root->left&&root->right)
		{
			tmp=Findmin(root->right);
			root->data=tmp->data;
			root->right=Delete(root->right,root->data);
		}
		else
		{
			if(!root->left)root=root->right;
			else if(!root->right)root=root->left;
			else free(tmp);
		}
	}
	return root;
}
int main()
{
	struct node* root=NULL;
	int n;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		int t;
		cin>>t;
		root=insert(root,t);
	}
	preorder(root);//先序遍歷 
	cout<<endl;
	levelorder(root);
	cout<<endl;
	cout<<getheight(root)<<endl;
	Delete(root,4);
	levelorder(root);
	cout<<endl;
	cout<<getheight(root)<<endl;
	return 0;
}