二叉树

#include "stdio.h"

#include "stdlib.h"



#define OVERFLOW -1

#define ERROR -1

#define OK 1



typedef char Elemtype;

typedef int Status;

typedef struct BitNode

{

	Elemtype data;

	struct BitNode *lchild,*rchild;

}bitnode ,*Bitree;







Status creatbitree(Bitree &t)

{

	char ch;

	scanf("%c",&ch);

	if(ch==' ') t=NULL;

	else

	{

		if(!(t=(bitnode *)malloc(sizeof(Bitree))))  exit(OVERFLOW);

		t->data=ch;

		creatbitree(t->lchild);

		creatbitree(t->rchild);

	}

	return OK;

}



Status printelemt(Elemtype e)

{

	printf("%c",e);

	return OK;

}



Status preordertraverse(Bitree t,Status (*visit)(Elemtype e))

{

	if(t)

	{

		if(visit(t->data))

			if(preordertraverse(t->lchild,visit))

					if(preordertraverse(t->rchild,visit))  return OK;

		return ERROR;

	}

	else 

		return OK;

}



Status inordertraverse(Bitree t,Status (*visit)(Elemtype e))

{

	if(t)

	{

	    if(inordertraverse(t->lchild,visit))

		    if(visit(t->data))

				if(inordertraverse(t->rchild,visit))  return OK;

		return ERROR;

	}

	else 

		return OK;

}



Status postordertraverse(Bitree t,Status (*visit)(Elemtype e))

{

	if(t)

	{

	    if(postordertraverse(t->lchild,visit))

			if(postordertraverse(t->rchild,visit))  	

					if(visit(t->data)) return OK;

		return ERROR;

	}

	else 

		return OK;

}



main()

{

	Bitree t;

	creatbitree(t);

	preordertraverse(t,printelemt);

	printf("\n");



	inordertraverse(t,printelemt);

	printf("\n");



	postordertraverse(t,printelemt);

	printf("\n");



}