C语言 二叉树构建与前中后序遍历

闲来无事，随手练练好久不用的数据结构编码，写一个创建二叉树和遍历二叉树的小程序，如有错误还请指正。

程序测试输入：1 2 3 -1 -1 4 -1 -1 5 -1 -1 -1 (“-1”输入作为标识符)，构建的二叉树结构如下图所示：

// 20130425.cpp : Defines the entry point for the console application.
/*@author: tjssehaige
@date: 2012/05/01
@notes: Create binary tree as well as traverse tree by preorder, inorder and postorder
@version: 1.0.0
*/
//

#include "stdafx.h"
#include <stdio.h>
#include <malloc.h>
/*Node structure for binary tree*/
typedef struct node{
int data; /*data field*/
node* left; /*left child pointer*/
node* right; /*right child pointer*/
}BNode, *BTree;

/*Create binary tree with numeric input*/
void CreateBinaryTree(BTree& tree){
int inputdata;
scanf("%d",&inputdata);
if(-1==inputdata){
tree=NULL;
}else{
if (!(tree=(BNode*)malloc(sizeof(BNode)))){
return;
}
/*recursively invoke function CreateBinaryTree*/
tree->data=inputdata;
CreateBinaryTree(tree->left);
CreateBinaryTree(tree->right);
}
return;
}
/*PreOrder Traverse*/
void preorderTraverse(BTree tree){
if (tree!=NULL){
printf("%d ", tree->data);
}
if (tree->left!=NULL){
preorderTraverse(tree->left);
}
if (tree->right){
preorderTraverse(tree->right);
}
}
/*InOrder Traverse*/
void inorderTraverse(BTree tree){
if (tree->left!=NULL){
inorderTraverse(tree->left);
}
if (tree!=NULL){
printf("%d ", tree->data);
}
if (tree->right!=NULL){
inorderTraverse(tree->right);
}
}
/*PostOrder Traverse*/
void postorderTraverse(BTree tree){
if (tree->left!=NULL){
postorderTraverse(tree->left);
}
if (tree->right!=NULL){
postorderTraverse(tree->right);
}
if (tree!=NULL){
printf("%d ", tree->data);
}
}
int _tmain(int argc, _TCHAR* argv[]){
BTree tree;
CreateBinaryTree(tree);
printf("PreOrder Traverse:");
preorderTraverse(tree);
printf("\n");
printf("InOrder Traverse:");
inorderTraverse(tree);
printf("\n");
printf("PostOrder Traverse:");
postorderTraverse(tree);
printf("\n");
return 0;
}