//递归实现
#include<iostream>
#include<string>
using namespace std;

typedef struct BiTNode{
    char data;
    struct BiTNode *lchild,*rchild;
}BiTNode,*BiTree;

void InitBiTree(BiTree &T)//构造空二叉树
{
    T=NULL;
}
void CreateBiTree(BiTree &T)//生成二叉树
{
    char ch;
    cin>>ch;
    if(ch==‘0‘)//0代表空
        T=NULL;
    else
    {
        T=(BiTree)malloc(sizeof(BiTNode));//生成根结点
        if(!T)
        {
            cout<<"生成结点错误！"<<endl;
            return;
        }
        T->data=http://www.mamicode.com/ch;
        CreateBiTree(T->lchild);
        CreateBiTree(T->rchild);
    }
}

void PreOrder(BiTree T)//先序递归遍历
{
    if(T!=NULL)
    {
        cout<<T->data<<" ";
        PreOrder(T->lchild);
        PreOrder(T->rchild);
    }
}

void InOrder(BiTree T)//中序递归遍历
{
    if(T!=NULL)
    {
        InOrder(T->lchild);
        cout<<T->data<<" ";
        InOrder(T->rchild);
    }
}

void PostOrder(BiTree T)//后序递归遍历
{
    if(T!=NULL)
    {
        PostOrder(T->lchild);
        PostOrder(T->rchild);
        cout<<T->data<<" ";
    }
}
int main()
{
    BiTree T;
    InitBiTree(T);
    cout<<"请输入二叉树结点"<<endl;
    CreateBiTree(T);
    string str="";
    cout<<"请输入遍历要求（先序,中序,后序）";
    cin>>str;
    if(str=="先序")
    {
        cout<<endl<<"先序递归遍历树"<<endl;
        PreOrder(T);
    }
    else if(str=="中序")
    {
        cout<<endl<<"中序递归遍历树"<<endl;
        InOrder(T);
    }
    else if(str=="后序")
    {
        cout<<endl<<"后序递归遍历树"<<endl;
        PostOrder(T);
    }
    cout<<endl;
    system("pause");
    return 0;
}