#include "iostream"
using namespace std;
#define max 20  //the number of node
typedef struct BTNode
{
	char data;
	struct BTNode *lc,*rc;
}BTree;

#define STACK_INIT_SIZE 100
#define STACK_INCR 10

typedef struct 
{ 
	BTree *base;
	BTree *top;
	int stackSize;
} Stack;

void initStack(Stack &stack)   //初始化棧
{ 
	stack.base = stack.top = (BTree *)malloc(sizeof(BTree) * STACK_INIT_SIZE);
	stack.stackSize = STACK_INIT_SIZE;
}

void pop(Stack &S, BTree * &T)  //出棧
{
	if(S.top == S.base) 
	{
		T = NULL;
		return ;
	}
	T = --S.top;
}

void push(Stack &S, BTree * &T)   //進棧
{
	if(S.top - S.base >= S.stackSize) 
	{
		S.base=(BTree*)realloc(S.base,(S.stackSize+STACK_INCR)*sizeof(BTree));
		S.top = S.base + S.stackSize;
		S.stackSize += STACK_INCR;
	}
	*S.top++ = *T;
}

bool stackEmpty(Stack S)   //判斷棧是否為空
{
	return S.top == S.base ? true : false;
}

BTree *createtree(char *str,int i,int m)  //建立樹
{
	BTree *p;
	if(i >= m)
		return 0;
	p = (BTree*)malloc(sizeof(BTree));
	p->data = str[i];
	p->lc = createtree(str,2*i+1,m);
	p->rc = createtree(str,2*i+2,m);
	return (p);
}

void PreOrder(BTree *t)  //樹的先序遍歷
{
	if(t != NULL)
	{
		cout<<t->data;
		if(t->lc)
		{
			cout<<"->";
			PreOrder(t->lc);
		}
		if(t->rc)
		{
			cout<<"->";
			PreOrder(t->rc);
		}
	}
}

void BiTreeCopy_Stack(BTree *root, BTree * ©root) //非遞迴複製二叉樹，將root複製到copyroot
{ 
	/*指標與引用的區別
	指標：存放變數地址的一個變數，邏輯上是獨立的，它可以被改變。
	引用：是一個別名，邏輯上不是獨立的，它的存在具有依附性，必須在一開始就被初始化，且"從一而終"
	*/
	Stack S1, S2;
	initStack(S1); //初始化棧
	initStack(S2);

	BTree *p = root;
	BTree *q, *pre;  //q用來每次建立新結點； pre為臨時根結點

	copyroot = pre = (BTree*)malloc(sizeof(BTree));

	while(p||!stackEmpty(S1)) //如果當前結點有左孩子，則一直向左走
	{
		while(p) 
		{ 
			q = (BTree*)malloc(sizeof(BTree));
			q->data = p->data;
			q->lc = q->rc = NULL;
			pre->lc = q;
			pre = q;
			push(S1, p);
			push(S2, q);
			p = p->lc;
		}

		pop(S1, p); //指標移到棧中最後一個元素
		pop(S2, q);

		while(!p->rc && !stackEmpty(S1))  //如果當前結點的右孩子為空，則棧中存放的左孩子全部出棧
		{
			pop(S1, p); 
			pop(S2, q);
		}

		p = p->rc; //p指向root中第一個有右孩子的結點
		q = q->rc;

		if(p) //對右子樹進行操作
		{
			q = (BTree*)malloc(sizeof(BTree));
			q->data = p->data;
			q->lc = q->rc = NULL;
			pre->rc = q;
			pre = q;
			push(S1, p);
			push(S2, q);
			p = p->lc;
		}
	}
	pre = copyroot; //使臨時根結點重新指回根結點
	copyroot = copyroot->lc;
	free(pre);   //釋放指臨時根結點
}

int main()
{
	int i,n;
	char str[max];
	BTree *root,*copyroot;

	cout<<"please input the number of node:";
	cin>>n;
	cout<<endl;

	cout<<"please input "<<n<<" nodes:";
	for(i = 0;i < n;i++)
		cin>>str[i];

	root = createtree(str,0,n); 
	cout<<"the PreOrder:";
	PreOrder(root);
	cout<<endl;

	BiTreeCopy_Stack(root, copyroot);
	cout<<"after the copy the PreOrder:";
	PreOrder(copyroot);
	cout<<endl;

	system("pause");
	return 0;
}