6-9 二叉树的遍历 (25分)

本题要求给定二叉树的4种遍历。

函数接口定义：

void InorderTraversal( BinTree BT );
void PreorderTraversal( BinTree BT );
void PostorderTraversal( BinTree BT );
void LevelorderTraversal( BinTree BT );

其中BinTree结构定义如下：

typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

要求4个函数分别按照访问顺序打印出结点的内容，格式为一个空格跟着一个字符。

裁判测试程序样例：

#include 
#include 

typedef char ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

BinTree CreatBinTree(); /* 实现细节忽略 */
void InorderTraversal( BinTree BT );
void PreorderTraversal( BinTree BT );
void PostorderTraversal( BinTree BT );
void LevelorderTraversal( BinTree BT );

int main()
{
    BinTree BT = CreatBinTree();
    printf("Inorder:");    InorderTraversal(BT);    printf("\n");
    printf("Preorder:");   PreorderTraversal(BT);   printf("\n");
    printf("Postorder:");  PostorderTraversal(BT);  printf("\n");
    printf("Levelorder:"); LevelorderTraversal(BT); printf("\n");
    return 0;
}
/* 你的代码将被嵌在这里 */

输出样例（对于图中给出的树）：

Inorder: D B E F A G H C I
Preorder: A B D F E C G H I
Postorder: D E F B H G I C A
Levelorder: A B C D F G I E H

void InorderTraversal( BinTree BT )//中序
{
    if(BT==NULL)
    {   
        return;
    }   
    InorderTraversal(BT->Left);
    printf(" %c",BT->Data);
    InorderTraversal(BT->Right);
}
void PreorderTraversal( BinTree BT )//前序
{
    if(BT==NULL)
    {   
        return;
    }   
    printf(" %c",BT->Data);
    PreorderTraversal(BT->Left);
    PreorderTraversal(BT->Right);
}
void PostorderTraversal( BinTree BT )//后序
{
    if(BT==NULL)
    {   
        return;
    }   
    PostorderTraversal(BT->Left);
    PostorderTraversal(BT->Right);
    printf(" %c",BT->Data);
}
void LevelorderTraversal( BinTree BT )//层序
{
    Position queue[10];//顺序存储
    Position record=NULL;//保存要打印的
    int rear=0;
    int front=0;
    if(BT==NULL)
        return ;
    else
    {   
        queue[rear]=BT;//BT不空就入队
        rear=(rear+1)%10;//循环队列
        while(front!=rear)//队列不空就打印并加上它的左右儿子
        {
            record=queue[front];
            front=(front+1)%10;
            printf(" %c",record->Data);
            if(record->Left)
            {
                queue[rear]=record->Left;
                rear=(rear+1)%10;   
            }
            if(record->Right)
            {
                queue[rear]=record->Right;
                rear=(rear+1)%10;
            }
        }
    }   
}

开始，层序也不会写，参见了这位的博客
dgyzmyx_

完整代码

#include 
#include 

typedef char ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

void InorderTraversal( BinTree BT );
void PreorderTraversal( BinTree BT );
void PostorderTraversal( BinTree BT );
void LevelorderTraversal( BinTree BT );
void Delete(BinTree BT);
BinTree CreatBinTree(void);

int main()
{
    BinTree BT = CreatBinTree();
    printf("Inorder:");  
    InorderTraversal(BT);
    printf("\n");
    printf("Preorder:");  
    PreorderTraversal(BT);
    printf("\n");
    printf("Postorder:");  
    PostorderTraversal(BT);
    printf("\n");
    printf("Levelorder:"); 
    LevelorderTraversal(BT);
    printf("\n");
    Delete(BT);
    return 0;
}
/* 你的代码将被嵌在这里 */
void Delete(BinTree BT)
{
    if(BT==NULL)
        return ;
    Delete(BT->Left);
    Delete(BT->Right);
    free(BT);

}
BinTree CreatBinTree(void)
{
    Position T=(Position)malloc(sizeof(struct TNode));
    if(!T)
    {   
        puts("It's full");
        exit(EXIT_FAILURE);
    }
    char ch;
    scanf("%c",&ch);
    if(ch=='#')
        T=NULL;
    else
    {   
        T->Data=ch;
        T->Left=T->Right=NULL;
        T->Left=CreatBinTree();
        T->Right=CreatBinTree();
    }
    return T;
}
void InorderTraversal( BinTree BT )//中序
{
    if(BT==NULL)
    {   
        return;
    }   
    InorderTraversal(BT->Left);
    printf(" %c",BT->Data);
    InorderTraversal(BT->Right);
}
void PreorderTraversal( BinTree BT )//前序
{
    if(BT==NULL)
    {   
        return;
    }   
    printf(" %c",BT->Data);
    PreorderTraversal(BT->Left);
    PreorderTraversal(BT->Right);
}
void PostorderTraversal( BinTree BT )//后序
{
    if(BT==NULL)
    {   
        return;
    }   
    PostorderTraversal(BT->Left);
    PostorderTraversal(BT->Right);
    printf(" %c",BT->Data);
}
void LevelorderTraversal( BinTree BT )//层序
{
    Position queue[10];//顺序存储
    Position record=NULL;//保存要打印的
    int rear=0;
    int front=0;
    if(BT==NULL)
        return ;
    else
    {   
        queue[rear]=BT;//BT不空就入队
        rear=(rear+1)%10;//循环队列
        while(front!=rear)//队列不空就打印并加上它的左右儿子
        {
            record=queue[front];
            front=(front+1)%10;
            printf(" %c",record->Data);
            if(record->Left)
            {
                queue[rear]=record->Left;
                rear=(rear+1)%10;   
            }
            if(record->Right)
            {
                queue[rear]=record->Right;
                rear=(rear+1)%10;
            }
        }
    }   
}

输入按先序，图例中，如此输入

ABD##FE###CG#H##I##