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 ");
}
}