#include <stdio.h>
#include <stdlib.h>

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;
}
void InorderTraversal( BinTree BT ){
    if(BT){
        InorderTraversal(BT->Left);
        printf(" %c",BT->Data);
        InorderTraversal(BT->Right);
    }
}
void PreorderTraversal( BinTree BT ){
    if(BT){
        printf(" %c",BT->Data);
        PreorderTraversal(BT->Left);
        PreorderTraversal(BT->Right);
    }
}
void PostorderTraversal( BinTree BT ){
    if(BT){
        PostorderTraversal(BT->Left);
        PostorderTraversal(BT->Right);
        printf(" %c",BT->Data);
    }
}
void LevelorderTraversal( BinTree BT ){
    BinTree q[100];
    int head=0,tail=0;
    if(BT)
        q[tail++]=BT;
    BinTree tmp;
    while(head<=tail-1){
        tmp = q[head++];
        printf(" %c",tmp->Data);
        if(tmp->Left)
            q[tail++]=tmp->Left;
        if(tmp->Right)
            q[tail++]=tmp->Right;
    }
}
BinTree CreatBinTree(){
    BinTree BT[9];
    int i;
    for(i=0;i<9;i++) {
        BT[i]=(BinTree)malloc(sizeof(struct TNode));
        BT[i]->Data=(char)(65+i);
    }
    BT[0]->Left=BT[1];
    BT[0]->Right=BT[2];
        BT[1]->Left=BT[3];
    BT[1]->Right=BT[5];
        BT[2]->Left=BT[6];
    BT[2]->Right=BT[8];
        BT[3]->Left=NULL;
    BT[3]->Right=NULL;
        BT[4]->Left=NULL;
    BT[4]->Right=NULL;
        BT[5]->Left=BT[4];
    BT[5]->Right=NULL;
        BT[6]->Left=NULL;
    BT[6]->Right=BT[7];
        BT[7]->Left=NULL;
    BT[7]->Right=NULL;
        BT[8]->Left=NULL;
    BT[8]->Right=NULL;
    return BT[0];
}