코드를 하나짰는데요 메모리 누수가 일어나는것 같네요

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
 
 
struct node
{
	int level;
	int key;
	int ch_key;
	struct node *left;
	struct node *right;
};
 
struct node*root = NULL;
void preorder(struct node*root);
void insert(struct node *root, int level, int key, int ch);
struct node * makeNode(int level, int key, int ch);
 
int main()
{
	int key, level, ch_key;
	char child[5];
	int i = 0;
	struct node*newnode = malloc(sizeof(struct node));
 
	while (i<10)
	{
		printf("for example you want to insert key 100 and level 1 and child_key 200 ----> 1 100 200\n");
		scanf("%d %d  %s", &level, &key, child);
 
		if (child == "NULL")
		{
			ch_key = '\0';
		}
		else ch_key = atoi(child);
 
		if (i == 0)
		{
			newnode->ch_key = ch_key;
			newnode->level = level;
			newnode->key = key;
 
			root = newnode;
		}
 
		else
			insert(root, level, key, ch_key);
		i++;
	}
 
 
 
	preorder(root);
 
 
 
	return 0;
}
struct node * makeNode(int level, int key, int ch) {
	struct node * newnode = malloc(sizeof(struct node));
	newnode->level = level;
	newnode->key = key;
	newnode->ch_key = ch;
	newnode->left = NULL;
	newnode->right = NULL;
	return newnode;
}
 
void insert(struct node *root, int level, int key, int ch)
{
 
 
	if (root->level == level)
	{
		if (root->right == NULL)
		{
			//newnode = makeNode(level,  key, ch);
			root->right = makeNode(level, key, ch);
			return;
		}
		else //root->right  !=  NULL
			insert(root->right, level, key, ch);//recursion
	}
	else //root->level  !=  newnode->level
	{
		if (root->ch_key == key)
		{
			//newnode = makeNode(level, key, ch);
			root->left = makeNode(level, key, ch);
			return;
		}
		else //root->ch_key  !=  newnode->key
		{
			if (root->left == NULL)
			{
				insert(root->right, level, key, ch);//recursion
			}
			else   // root !=NULL
			{
				insert(root->left, level, key, ch);//recursion
			}
		}
 
	}
 
 
}
 
 
void preorder(struct node *root) {
 
	if (root!=NULL)
	{
		printf("%d\n", root->key);
		preorder(root->left);
		preorder(root->right);
	}
}