#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef char TElemType;


typedef struct BiTNode
{
    TElemType data;
    struct BiTNode *Lchild;
    struct BiTNode *Rchild;
}BiTNode,*BiTree;

void CreateBiTree(BiTree &root)
{
    char ch;
    ch=getchar();
    if(ch=='#') root=NULL;
    else
    {
        root=(BiTree)malloc(sizeof(BiTNode));
        root->data=ch;
        CreateBiTree(root->Lchild);
        CreateBiTree(root->Rchild);
    }
}

void PreOrder(BiTree &root)
{
    if(root!=NULL)
    {
        printf("%c",root->data);
        PreOrder(root->Lchild);
        PreOrder(root->Rchild);
    }
}

void InOrder(BiTree &root)
{
    if(root!=NULL)
    {
        InOrder(root->Lchild);
        printf("%c",root->data);
        InOrder(root->Lchild);
    }
}

void PostOrder(BiTree &root)
{
    if(root!=NULL)
    {
        PostOrder(root->Lchild);
        PostOrder(root->Rchild);
        printf("%c",root->data);
    }
}

int leaf(BiTree &root)
{
    int LeafCount;
    if(root==NULL)
        LeafCount=0;
    else if((root->Lchild==NULL)&&(root->Rchild==NULL))
        LeafCount=1;
    else
        LeafCount=leaf(root->Lchild)+leaf(root->Rchild);
    return LeafCount;
}

void main()
{
    BiTree T;
    int a,b;
    scanf("%s",&T);
    CreateBiTree(T);
    printf("先序遍历:1");
    printf("中序遍历:2");
    printf("后序遍历:3");
    printf("叶子结点总数:4");
    printf("退出:0");
    scanf("%d",&a);
    while(a!=0)
    {
        switch(a)
        {
        case 1:PreOrder(T);
            printf("\n");
            break;
        case 2:InOrder(T);
            printf("\n");
            break;
        case 3:PostOrder(T);
            printf("\n");
            break;
        case 4:printf("叶子结点总数为:");
            b=leaf(T);
            printf("%d",b);
            printf("\n");
        default:printf("error\n");
        }
        printf("先序遍历:1");
        printf("中序遍历:2");
        printf("后序遍历:3");
        printf("叶子结点总数:4");
        printf("退出:0");
        scanf("%d",&a);
    }
}
在输入的时候为什么输入不进去?