非递归法遍历二叉树

前序遍历

void UnRecPreTraversal(BinaryTree *pTree)
{
	if(pTree == NULL)return;
	//申请辅助栈
	Stack *pStack = NULL;
	s_Init(&pStack);
	while(1)
	{
		//当前节点非空
		while(pTree)
		{
			//打印 入栈 向左走
			printf("%d ",pTree->nValue);
			s_Push(pStack,pTree);
			pTree = pTree->pLeft;
		}
		//弹出
		pTree = s_Pop(pStack);	
		//栈空 结束
		if(pTree == NULL)break;
		//右
		pTree = pTree->pRight;
	}
}

中序遍历

void UnRecInTraversal(BinaryTree *pTree)
{
	if(pTree == NULL)return;

	//申请辅助栈
	Stack *pStack = NULL;
	s_Init(&pStack);

	while(1)
	{
		//当前节点非空
		while(pTree)
		{
			// 入栈 向左走
			s_Push(pStack,pTree);
			pTree = pTree->pLeft;
		}

		//弹出
		pTree = s_Pop(pStack);
		
		//栈空 结束
		if(pTree == NULL)break;
		
		//打印
		printf("%d ",pTree->nValue);
		//右
		pTree = pTree->pRight;
	}
}

后续遍历

void UnRecLastTraversal(BinaryTree *pTree)
{
	if(pTree == NULL)return;

	//辅助栈
	Stack *pStack = NULL;
	s_Init(&pStack);

	BinaryTree *pMark = NULL;

	while(1)
	{
		while(pTree)
		{
			s_Push(pStack,pTree);
			pTree = pTree->pLeft;
		}
		
		if(pStack->pTop == NULL)break;

		if(pStack->pTop->nValue->pRight == NULL || pStack->pTop->nValue->pRight == pMark)
		{
			//弹出 标记 打印
			pMark = s_Pop(pStack);
			printf("%d ",pMark->nValue);
		}
		else
		{
			//右 非空 且未被标记
			pTree = pStack->pTop->nValue->pRight;
		}
	}