#include<stdio.h>
#include<stdlib.h>
#define OK 1
#define ERROR 0
#define OVERFLOW 3
 
typedef int Status;  
typedef int Boolean; 
typedef char TElemType;
 
typedef struct BiTNode{
	TElemType	   data;
	struct BiTNode *lchild, *rchild;
}BiTNode, *BiTree;
 
//創建二叉樹函數
 
Status CreateBiTree(BiTree &T){
	TElemType ch;
	scanf("%c", &ch);
	getchar();
	if(ch == ' '){	T = NULL;}
	else {
		if( !(T=(BiTree)malloc(sizeof(BiTNode))))(exit(OVERFLOW));
		T->data = ch;				
		printf("%c的左子樹：", ch);
		CreateBiTree(T->lchild);		
		printf("%c的右子樹：", ch);
		CreateBiTree(T->rchild);	}
	return OK;
}
 
//先序遍歷函數
Status PreOrderTraverse(BiTree T, Status (* Visit)(TElemType e)){
	if(T){
		if(Visit(T->data)){
			if(PreOrderTraverse(T->lchild, Visit)){
				if(PreOrderTraverse(T->rchild, Visit)){
					return OK;
               }	
            }	
         }
		return ERROR;
    }
	else {return OK;}
}
 
//中序遍歷函數
Status InOrderTraverse(BiTree T, Status (* Visit)(TElemType e)){
	if(T){
		if(PreOrderTraverse(T->lchild, Visit) ){
			if(Visit(T->data)){
				if(PreOrderTraverse(T->rchild, Visit) ){
					return OK;
           }
	   }	
   }
		return ERROR;
        }
	else {
		return OK;
        }
	}
 
//后序遍歷函數
Status PosOrderTraverse(BiTree T, Status (* Visit)(TElemType e)){
	if(T){
		if(PreOrderTraverse(T->lchild, Visit) ){
			if(PreOrderTraverse(T->rchild, Visit) ){
				if(Visit(T->data)){return OK;
}
	}	
}
		return ERROR;}
	else {return OK;
}
}
 
 
//輸出二叉樹函數
Status PrintElement(TElemType e){	
	printf("%c",e);
	return OK;
}
 
//主函數
int main(){
	BiTree T;
	printf("輸入根結點：");
	CreateBiTree(T);
	printf("先序遍歷：\n");
	PreOrderTraverse(T, PrintElement);
	printf("\n");
	printf("中序遍歷：\n");
	InOrderTraverse(T, PrintElement);
	printf("\n");
	printf("后序遍歷：\n");
	PosOrderTraverse(T, PrintElement);
	return 0;
}