数据结构之树和二叉树---二叉树的遍历

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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);}elseprintf("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);}elseprintf("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);}elseprintf("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);}elseprintf("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);}elseprintf("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);elseprintf("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);}elseprintf("0 ");}}

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