二叉树的前序遍历、中序遍历、后序遍历

#include <iostream>
#include <string>
#include <stack>
#include <vector>
using namespace std;
#define MAXNODE 7
typedef int DATATYPE;
typedef struct TreeNode
{
  DATATYPE data;
  TreeNode *left;
  TreeNode *right;
}TreeNode;
TreeNode *mallocBinaryNode(int data)
{
  TreeNode *node = (TreeNode*)malloc(sizeof(TreeNode));
  node->data = data;
  node->left = node->right = NULL;
  return node;
}
TreeNode *createBinaryTree(char buf[], int num)
{
  TreeNode *node = mallocBinaryNode(buf[num]);
  // printf("node_id:%d, node_data:%d\n", num, node->data);
  if (2 * num <= MAXNODE)
  {
    node->left = createBinaryTree(buf, 2 * num);
  }
  if (2 * num + 1 <= MAXNODE)
  {
    node->right = createBinaryTree(buf, 2 * num + 1);
  }
  return node;
}
void preOrder(TreeNode *node)    // 前序遍历，中左右
{
  if (node != NULL)
  {
    cout << node->data << " ";
    preOrder(node->left);
    preOrder(node->right);
  }
}
void inOrder(TreeNode *node)     // 中序遍历，左中又
{
  if (node != NULL)
  {
    inOrder(node->left);
    cout << node->data << " ";
    inOrder(node->right);
  }
}
void postOrder(TreeNode *node)     // 后序遍历，左右中
{
  if (node != NULL)
  {
    postOrder(node->left);
    postOrder(node->right);
    cout << node->data << " ";
  }
}
void testTree()
{
  TreeNode *root;
  char buf[] = {0,11,12,13 ,14, 15, 16, 17};
  root = createBinaryTree(buf, 1);
  preOrder(root);
  cout << endl;
  inOrder(root);
  cout << endl;
  postOrder(root);
  cout << endl;
}