simpletree

#ifndef _SIMPLETREE_H_
#define _SIMPLETREE_H_

typedef struct _node {
	int m_data;
	struct _node* m_left;
	struct _node* m_right;
} node_t;

void tree_insert  (node_t** root, int data);
void tree_remove  (node_t** root, int data);
void tree_display (node_t* root, int index);
void tree_distroy (node_t** root);

#endif

#include <stdio.h>
#include <malloc.h>
#include "simpletree.h"

node_t** tree_findNode (node_t** root, int data);
node_t** tree_findPre  (node_t** root);

void tree_insert  (node_t** root, int data) {
	if (!(*root)) {
		*root = (node_t*)malloc(sizeof(node_t));
		(*root)->m_left = 0;
		(*root)->m_right = 0;
		(*root)->m_data = data;
	}
	else if ((*root)->m_data > data) {
		tree_insert (&(*root)->m_left, data);
	}
	else {
		tree_insert (&(*root)->m_right, data);
	}
}

void tree_remove  (node_t** root, int data) {
	node_t **thisnode, **prenode, *tmp;
	thisnode = tree_findNode (root, data);
	if (!(*thisnode)) {
		return;
	}
	prenode = tree_findPre (&(*thisnode)->m_left);
	if (!(*prenode)) {
		tmp = *thisnode;
		*thisnode = (*thisnode)->m_right;
		free (tmp);
	}
	else {
		tmp = *prenode;
		(*thisnode)->m_data = (*prenode)->m_data;
		*prenode = (*prenode)->m_left;
		free (tmp);
	}
}

void tree_display (node_t* root, int index) {
	int cusor;
	if (!root) {
		return;
	}
	tree_display (root->m_right, index + 1);
	for (cusor = 0; cusor < index; ++cusor) {
		printf ("   ");
	}
	printf ("%d\n",root->m_data);
	tree_display (root->m_left, index + 1);
}

void tree_destroy (node_t** root) {
	if (!(*root)) {
		return;
	}
	tree_destroy (&(*root)->m_left);
	tree_destroy (&(*root)->m_right);
	free (*root);
	*root = 0;
}

node_t** tree_findNode (node_t** root, int data) {
	if (!(*root) || (*root)->m_data == data) {
		return root;
	}
	if ((*root)->m_data > data) {
		return tree_findNode (&(*root)->m_left, data);
	}
	return tree_findNode (&(*root)->m_right, data);	
}

node_t** tree_findPre (node_t** root) {
	if (!(*root) || !(*root)->m_right) {
		return root;
	}
	return tree_findPre (&(*root)->m_right);
}

int main () {
	node_t* root = 0;
	tree_insert (&root, 20);
	tree_insert (&root, 10);
	tree_insert (&root, 40);
	tree_insert (&root, 5);
	tree_insert (&root, 1);
	tree_insert (&root, 7);
	tree_insert (&root, 15);
	tree_insert (&root, 12);
	tree_insert (&root, 16);
	tree_insert (&root, 32);
	tree_insert (&root, 27);
	tree_insert (&root, 38);
	tree_insert (&root, 45);
	tree_insert (&root, 41);
	tree_insert (&root, 51);

	tree_display (root, 0);
	
	tree_remove (&root, 20);
	tree_remove (&root, 45);

	printf ("---------------\n");
	tree_display (root, 0);
	tree_destroy (&root);

	return 0;
}