二叉树(创建、先序、中序、后序遍历)

二叉树的创建与遍历：

#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
char *str="";
//二叉树结点的定义
typedef struct BTNode
{
char data;
struct BTNode *lc;
struct BTNode *rc;
}BTNode,*BiTree;

void Creat(BiTree &T)
{
    char ch[2];
    scanf("%s",&ch[0]);
//cin.get(ch);
    if(strcmp(ch,"@")==0) T=NULL;
    else{
        T=new BTNode;
        T->data=ch[0];
        Creat(T->lc);
        Creat(T->rc);
    }
}

//先序遍历
void PreOrder(BiTree T)
{
    if(T)
    {
        cout<<T->data<<' ';
        PreOrder(T->lc);
        PreOrder(T->rc);
    }
}

//中序遍历
void InOrder(BiTree T)
{
    if(T)
    {
        InOrder(T->lc);
        cout<<T->data<<' ';
        InOrder(T->rc);
    }
}

//后序遍历
void PostOrder(BiTree T)
{
    if(T)
    {
        PostOrder(T->lc);
        PostOrder(T->rc);
        cout<<T->data<<' ';
    }
}


int main()
{
    int c;
    BiTree T;
    printf("Input nodes of binary tree:(NULL<=>'@')\n");
    Creat(T);
    while(1)
    {
        cout<<"\nPlease select a service:\n";
        cout<<"\n1:PreOrder Traverse\n2:InOrder Traverse\n3:PostOrder Traverse\n0:Exit\n";
        cin>>c;
        switch(c)
        {
            case 1:{cout<<"\nPreOrder traverse:\n"; PreOrder(T); break;}
            case 2:{cout<<"\nInOrder traverse:\n";InOrder(T);break;}
            case 3:{cout<<"\nPostOrder traverse:\n";PostOrder(T);break;}
            default:{cout<<"Game Over!\n";return 0;}
        }
    }
}