数据结构之树和二叉树---二叉树的遍历

问题：分别用递归和非递归方式实现二叉树的先序遍历，中序遍历，后序遍历及层序遍历

二叉树的基本操作见数据结构之树和二叉树---二叉树的基本操作

//递归方式实现先序遍历

void PreOrderTraverse(BiTree bt)
{
	if(bt)
	{
		printf("%c ", bt->data);
		PreOrderTraverse(bt->lchild);
		PreOrderTraverse(bt->rchild);
	}else
		printf("0 ");
}

//递归方式实现中序遍历

void InOrderTraverse(BiTree bt)
{
	if(bt)
	{
		InOrderTraverse(bt->lchild);
		printf("%c ", bt->data);
		InOrderTraverse(bt->rchild);
	}else
		printf("0 ");
}

//递归方式实现后序遍历

void PostOrderTraverse(BiTree bt)
{
	if(bt)
	{
		PostOrderTraverse(bt->lchild);
		PostOrderTraverse(bt->rchild);
		printf("%c ", bt->data);
	}else
		printf("0 ");
}

//递归方式实现层序遍历

void LevelOrderTraverse(BiTree bt, LinkQueue *lq)
{
	ElemType elem;
	if(lq->front!=lq->rear)
	{
		DeQueue(lq, &elem);
		if(elem!=NULL)
		{
			printf("%c ", elem->data);
			EnQueue(lq, elem->lchild);
			EnQueue(lq, elem->rchild);
		}else
			printf("0 ");
		LevelOrderTraverse(bt, lq);
	}
}

//非递归方式实现先序遍历

void PreOrderTraverse_N_Recur(BiTree bt)
{
	ElemType stackElem;
	MyStack *stack = InitStack();
	PushStack(stack, bt);

	while(stack->top!=stack->base)
	{
		PopStack(stack,&stackElem);
		if(stackElem!=NULL)
		{
			printf("%c ", stackElem->data);
			PushStack(stack,stackElem->rchild);
			PushStack(stack, stackElem->lchild);
		}else
			printf("0 ");
	}
}

//非递归方式中序遍历

void InOrderTraverse_N_Recur(BiTree bt)
{
	ElemType stackElem;
	MyStack *stack = InitStack();
	PushStack(stack, bt);

	while(stack->top!=stack->base)
	{
		while((stackElem=(*(stack->top-1))->lchild)!=NULL)
			PushStack(stack, stackElem);
		do
		{
			printf("0 ");
			PopStack(stack, &stackElem);
			printf("%c ", stackElem->data);
		}while(!stackElem->rchild&&stack->top!=stack->base);
		if(stackElem->rchild!=NULL)
			PushStack(stack, stackElem->rchild);
		else
			printf("0 ");
	}
}

//非递归方式后序遍历

void PostOrderTraverse_N_Recur(BiTree bt)
{
	ElemType stackElem;
	MyStack *stack = InitStack();
	BiTNode *tbn;
	PushStack(stack, bt);

	while(stack->top!=stack->base)
	{
		while((stackElem=*(stack->top-1))->lchild!=NULL)
			PushStack(stack, stackElem->lchild);
		printf("0 ");
		if(stackElem->rchild!=NULL)
			PushStack(stack, stackElem->rchild);
		else
		{
			printf("0 ");
			PopStack(stack, &stackElem);
			while (stack->top!=stack->base)
			{
				while((*(stack->top-1))->rchild==stackElem)
				{
					printf("%c ", stackElem->data);
					PopStack(stack, &stackElem);
					if (stack->top==stack->base)
					{
						printf("%c ", stackElem->data);
						return ;
					}
				}
				if((*(stack->top-1))->lchild==stackElem)
				{
					printf("%c ", stackElem->data);
					if((*(stack->top-1))->rchild!=NULL)
					{
						PushStack(stack, (*(stack->top-1))->rchild);
						break;
					}
					else
					{
						printf("0 ");
						PopStack(stack, &stackElem);
					}
				}
			}
		}
	}
	return ;
}

//非递归方式实现层序遍历

void LevelOrderTraverse_N_Recur(BiTree bt)
{
	ElemType elem;
	LinkQueue *lq = InitQueue();

	EnQueue(lq, bt);
	while(lq->front!=lq->rear)
	{
		DeQueue(lq, &elem);
		if(elem!=NULL)
		{
			printf("%c ", elem->data);
			EnQueue(lq, elem->lchild);
			EnQueue(lq, elem->rchild);
		}else
			printf("0 ");
	}
}