主要功能：创建二叉排序树，中序遍历，结点取3的模，0，1，2个各输出不同的值。 2003.
#include "stdafx.h"
#include<iostream>
#include"tree.h"
#define MAX 100
using namespace std;


//定义树节点的结构体
typedef struct _ml_YYY_Node
{
   int data;
   struct _ml_YYY_Node * lc;
   struct _ml_YYY_Node * rc;
}ml_YYY_BTree;//定义树结点的结构体


//二叉排序树的类定义
class ml_YYY_CreateTree
{
public:
    ml_YYY_CreateTree(int r[],int n);
    
    virtual ~ml_YYY_CreateTree();
    void ml_YYY_InSert(ml_YYY_BTree * root , ml_YYY_BTree * s);//在二叉树中插入结点
    void mlYYYinOrder(ml_YYY_BTree * root);//中序遍历
private:
    ml_YYY_BTree * root;
    ml_YYY_BTree * s;  //二叉排序树的根指针
};



//插入操作
void ml_YYY_CreateTree::ml_YYY_InSert(ml_YYY_BTree * root , ml_YYY_BTree * s)
{
    if(root == NULL)
    {
        root = s ;
    }
    else if(s->data < root->data)
    {
        ml_YYY_InSert(root->lc , s);
    }
    else
    {
        ml_YYY_InSert(root->rc , s);
    }
}





//二叉排序树的构造算法
ml_YYY_CreateTree::ml_YYY_CreateTree(int r[],int n)
{    
      for(int i = 0;i < n;i++)
      {
          s=(ml_YYY_BTree*)malloc(sizeof(ml_YYY_BTree));
          if(s == NULL)
          {
              cout<<"Not Enough Memory!\n" ;
          }
          else
          {
            s->data = r[i];
            s->lc = NULL;
            s->rc = NULL;
            ml_YYY_InSert( root , s);
          }
  }
}



//多态输出结果

class mlYYYshow
{
public:
    virtual void disPlay(int n);
private:
    int n;
};

class mlYYYcircleShow:public  mlYYYshow
{
 public:
    void disPlay(int n)
    {
        if(n%3 == 0)
        {
            cout<<"Circle-"<<endl;
        }
    }
};

class mlYYYtriangleShow:public  mlYYYshow
{
public:
    void disPlay(int n)
    {
        if(n%3 == 1)
        {
            cout<<"Triangle-"<<endl;
        }
    }
};

class mlYYYrectangleShow:public  mlYYYshow
{
public:
    void disPlay(int n)
    {
        if(n%3 == 2)
        {
            cout<<"Rectangle-"<<endl;
        }
    }
};





//树的中序遍历算法
void ml_YYY_CreateTree:: mlYYYinOrder(ml_YYY_BTree * root)
{
    if(root == NULL)
    {
        cout<<"the tree is null."<<endl;
    }
    else
    {
        mlYYYshow show;
        mlYYYinOrder(root->lc);
        show.disPlay(root->data);
        mlYYYinOrder(root->rc);

    }
}





void main()
{
  int i,j,n;
  int a[MAX];
  cout<<"intput the number of the ver "<<endl;
  cin >> n >>endl;
  cout<<"请输入数字构造二叉树："<<endl;
  for(i=0;i<n;i++)
  {
      cin >> a[i] >>endl;
      if(a[i] < 0 || !cin)
    {
        cout<<"输入有误，请重新输入数字："<<endl;
        cin.clear(); //清除错误标记
        cin.get(); //清除输入缓冲区
      }
  }
   ml_YYY_BTree * Tree ;
   Tree = ml_YYY_CreateTree(a, n);
   cout<<"中序遍历树,输出如下："<<endl;
   mlYYYinOrder(Tree);
}
编译的错误如下：
error C2440: '=' : cannot convert from 'ml_YYY_CreateTree' to 'ml_YYY_BTree *'No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
error C2679: binary '>>' : no operator found which takes a right-hand operand of type 'overloaded-function' (or there is no acceptable conversion)
error C3861: 'mlYYYinOrder': identifier not found, even with argument-dependent lookup
error C2679: binary '>>' : no operator found which takes a right-hand operand of type 'overloaded-function' (or there is no acceptable conversion)