#include<stdio.h>
#include<malloc.h>
typedef char ElemType;
typedef struct BiTNode {
	ElemType data;
	struct BiTNode* lchild, * rchild;
}BiTNode,*BiTree;
BiTNode* p=(BiTree)malloc(sizeof(BiTNode));		//记录目标节点
BiTNode* pre = NULL;	//指向当前访问节点的前驱
BiTNode* final;	//记录最终结果
bool IniTree(BiTree &T)
{
	ElemType ch;
	ch = getchar();
	if (ch == '#')
	{
		T = NULL;
	}
	else {
		T = (BiTree)malloc(sizeof(BiTNode));
		T->data = ch;
		if (T->lchild != NULL)
			IniTree(T->lchild);
		if (T->rchild != NULL)
			IniTree(T->rchild);
	}
	return true;
}
void visit(BiTree t)
{
		printf("%c\t", t->data);
}
void visitPre(BiTree t)
{
	if (t->data == p->data)
		final = pre;
	else
		pre = t;	//pre指向当前访问的节点
}
bool InOrder1(BiTree t)
{
	if (t == NULL)
	{
		return false;
	}
	if(t!=NULL)
	{
		InOrder1(t->lchild);
		visit(t);
		InOrder1(t->rchild);
		return true;
	}
}
bool InOrder2(BiTree t)
{
	if (t == NULL)
	{
		return false;
	}
	if (t != NULL)
	{
		InOrder2(t->lchild);
		visitPre(t);
		InOrder2(t->rchild);
		return true;
	}
}
int main()
{
	BiTree T;
	p->data='D';
	printf("初始化二叉树,ps:#表示空树：");
	IniTree(T);
	printf("\n二叉树中序遍历：");
	InOrder1(T);
	InOrder2(T);
	if (final != NULL)
		printf("\n节点%c中序前驱：%c", p->data, final->data);
	else
		printf("\n节点%c无前驱\n");
	return 0;
}