#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include<string.h>
#define MAX 100
int top = -1;
typedef struct tnode {
    int data;
    struct tnode *lchild; 
	struct tnode *rchild;
}BTNode, *BTree;
typedef struct Queue{
	BTree data;
	struct Queue* next;
}Qnode;
typedef struct point{
	Qnode* front;//头指针
	Qnode* rear;//尾指针
}LinkQueue;
BTree CreatBTree(){
    int num;
    BTree p;
    scanf("%d", &num);
    if (num == -1) {
        p = NULL;
    } else {
        p = (BTree) malloc(sizeof(BTNode));
        p->data = num;
        printf("请输入 %d 的左子树:\n", num);
        p->lchild = CreatBTree();
        printf("请输入 %d 的右子树:\n", num);
        p->rchild = CreatBTree();
    }
    return p;
}
void PreOrder(BTree tree){
    if(tree == NULL){
		return;
	}
	printf("%d", tree->data);
    PreOrder(tree->lchild);
    PreOrder(tree->rchild);
}
void InOrder(BTree tree){
    if(tree == NULL){
		return;
	}
    InOrder(tree->lchild);
    printf("%d", tree->data);
    InOrder(tree->rchild);
}
void LastOrder(BTree tree){
    if(tree == NULL){
		return;
	}
    LastOrder(tree->lchild);
    LastOrder(tree->rchild);
    printf("%d", tree->data);
}
void push(BTree a[],BTree node){
    a[++top] = node;
}
void pop(){
    if (top == -1) {
        return;
    }
    top--;
}
BTree getTop(BTree a[]){
    return a[top];
}
void InOrder2(BTree Tree){
	top = -1;
    BTree a[MAX],p;
    push(a, Tree);
    while (top != -1) {
        while ((p = getTop(a)) && p != NULL){
            push(a, p->lchild);
        }
        pop();
        if (top != -1) {
            p = getTop(a);
            pop();
            printf("%d", p->data);
            push(a, p->rchild);
        }
    }
}
void InitQueue(LinkQueue* q){
	q->front = q->rear = (Qnode*)malloc(sizeof(Qnode));
	if (q->front == NULL)
		return;
}
void EnQueue(LinkQueue* q, BTree ele){
	Qnode* p = (Qnode*)malloc(sizeof(Qnode));
	if (p == NULL) {
		return;
	}
	if (ele == NULL)
		return;
	p->data = ele;
	p->next = NULL;
	q->rear->next = p;
	q->rear = p;
}
int QueueEmpty(LinkQueue q)
{
	if (q.front != q.rear)
		return 1;
	else
		return 0;
}
BTree DeQueue(LinkQueue* q)
{
	if (q->front == q->rear){
		return;
	}
	Qnode* p = q->front->next;
	BTree q_ = p->data;
	q->front->next = p->next;
	if (q->rear == p)
		q->rear = q->front;
	free(p);
	return q_;
}
void LevelOrder(BTree Tree){
	top = -1;
    BTree p;
    LinkQueue Q1;
	InitQueue(&Q1);
    EnQueue(&Q1, Tree);
    while (QueueEmpty(Q1)) {
    	p = DeQueue(&Q1);
        printf("%d  ", p->data);
        if (p->lchild != NULL) {
		    EnQueue(&Q1, p->lchild);
		}
		if (p->rchild != NULL) {
		    EnQueue(&Q1, p->rchild);
		}
    }
}
int main(){
	int choice;
	BTree tree;
	
	for(;;){
		printf("\t\t1.递归先序建立二叉树\n");
		printf("\t\t2.先序遍历二叉树\n");
		printf("\t\t3.中序遍历二叉树\n");
		printf("\t\t4.后序遍历二叉树\n");
		printf("\t\t5.中序非递归遍历二叉树\n");
		printf("\t\t6.层次遍历二叉树\n");
		printf("\t\t0.退出\n");
		
		printf("请选择：");
		scanf("%d",&choice);
		if(choice==0) break;
		switch (choice) {
		case 1:
			printf("开始先序创建二叉树，输入 -1 为空节点\n");
			tree = CreatBTree();
			break;
		case 2:
			PreOrder(tree);
			printf("\n");
			break;
		case 3:
			InOrder(tree);
			printf("\n");
			break;
		case 4:
			LastOrder(tree);
			printf("\n");
			break;
		case 5:
			InOrder2(tree);
			printf("\n");
			break;
		case 6:
			LevelOrder(tree);
			printf("\n");
			break;
		default:
			break;
		}
		printf("请按任意键继续...");
		getch();
		system("cls");
	}
    printf("感谢使用，再见\n");
	return 0;
}