二叉树插入Demo

今天群上一个人说递归的二叉树插入不知道怎么做，于是我就帮忙写了个简单的demo

// binary_tree.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <stdlib.h>

typedef struct node{
	int value;
	node* left;
	node* right;
}node;

/*print the tree left-mid-right order*/
void printTree(node* root){
	if(root == NULL)
		return;
	printTree(root->left);
	printf("%d,",root->value);
	printTree(root->right);
}

/*make node*/
node* makeNode(){
	node* n = (node*) malloc(sizeof(node));
	n->value = 0;
	n->left = NULL;
	n->right = NULL;
	return n;
}

/*to insert a value into the binary tree, return the new root*/
node* insert(node* root, int value){
	if(root == NULL){
		root = makeNode();
		root->value = value;
	}else if(value < root->value){// insert to the left
		root->left = insert(root->left,value);
	}else{// insert to the right
		root->right = insert(root->right,value);
	}
	return root;
}

int main(int argc,char* argv[]){
	node* root = NULL;
	int data[10] = {3,2,1,4,6,8,7,10,9,33};
	for(int i=0;i<10;i++){
		root = insert(root,data[i]);
	}
	printTree(root);
	system("pause");
	return 0;
}