两种方法C实现二叉树的创建和遍历

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

typedef struct node {
	int data;
	struct node *left;
	struct node *right;
} node_t;

typedef struct tree {
	struct node *root;
} tree_t;


node_t *alloc_one(int data) {
	node_t *p = (node_t *)malloc(sizeof(node_t));
	p->data = data;
	p->left = NULL;
	p->right = NULL;

	return p;
}

// 方法1:
void insert_one(tree_t *t, int data) {
	node_t *new = alloc_one(data);

	if (t == NULL) {
		t = new;
	} else {
		node_t *tmp = t->root;

		while (tmp) {
			if (data < tmp->data) {
				if (tmp->left == NULL) {
					tmp->left = new;
					return;
				} else {
					tmp = tmp->left;
				}
			} else if (data > tmp->data) {
				if (tmp->right == NULL) {
					tmp->right = new;
					return;
				} else {
					tmp = tmp->right;
				}
			}
		}
	}
}

// 方法2：递归法
node_t *insert_one2(node_t *t, int data) {
	node_t *new = alloc_one(data);

	if (t == NULL) {
		t->root = new;
	} else {
		node_t *tmp = t->root;

		if (data < tmp->data) {
			if (tmp->left == NULL) {
				tmp->left = new;
				return tmp->left;
			} else {
				insert_one2(tmp->left, data);
			}
		} else {
			if (tmp->right == NULL) {
				tmp->right = new;
				return tmp->right;
			} else {
				insert_one2(tmp->right, data);
			}
		}
	}

	return t;
}


void inOrder(struct node_t *root, int *res, int *resSize) {

	if (!root) {
		return;
	}

	inOrder(root->left, res, resSize);
	res[(*resSize++)] = root->data;
	inOrder(root->right, res, resSize);
}

int* inOrderTraverse(struct node_t *root, int *returnSize) {
	int *res = malloc(sizeof(int) * 100);
	*returnSize = 0;

	inOrder(root, res, returnSize);
}

int main() {
	int dataList[3] = {3, 5, 19};
	int i;

	tree_t *my_tree;
	my_tree->root = NULL;

	for(i = 0; i < sizeof(dataList)/sizeof(int); i++) {
		insert_one(my_tree, i);
	}

	return 0;
}