二叉树（按层遍历——队列模拟）

"队列.h"文件

#include 
#include 

typedef struct biTree elemType ;

struct node{
	elemType * elem;
	struct node * next;
};

struct queue{
	struct node * front;
	struct node * rear;
};

struct queue * initQueue();

struct queue * enQueue(struct queue * q,elemType elem);

struct queue * deQueue(struct queue * q);



struct queue * initQueue(){
	struct queue * q;
	q=(struct queue *)malloc(sizeof(struct queue));
	q->front=(struct node *)malloc(sizeof(struct node));
	q->rear=q->front;
	q->front->next=NULL;
	return q;
}

struct queue * enQueue(struct queue * q,elemType * elem){
	struct node * p;
	p=(struct node *)malloc(sizeof(struct node));
	p->elem=elem;
	p->next=NULL;
	q->rear->next=p;
	q->rear=p;
	return q;
}

struct queue * deQueue(struct queue * q){
	struct node * p;
	if(q->front==q->rear){
		printf("队列为空！无法删除!\n");
	}
	else{
		p=q->front->next;
		q->front->next=p->next;
		if(q->rear==p){
			q->rear=q->front;
		}
		free(p);
	}
	return q;
}


"二叉树.h"文件

#define  _CRT_SECURE_NO_WARNINGS 
#include 
#include 

struct biTree{
	char data;
	struct biTree * lchild, * rchild;
};

struct biTree * initBiTree();

struct biTree * createBiTree(struct biTree * bt);

int preOrderTraverse(struct biTree * bt);

int inOrderTraverse(struct biTree * bt);

int postOrderTraverse(struct biTree * bt);

int levelOrderTraverse(struct biTree * bt);

int test();



.c文件

#include "二叉树.h"
#include "队列.h"

#define MAX 100

struct biTree * createBiTree(struct biTree * bt){
	int front,rear;
	char ch;
	struct biTree * p,* Queue[MAX];
	front=1,rear=0;
	printf("按层输入二叉树，虚结点输入'#'(结束符为'@')：\n");
	while((ch=getchar())!='@'){
		p=NULL;
		if(ch!='#'){
			p=(struct biTree *)malloc(sizeof(struct biTree));
			p->data=ch;
			p->lchild=p->rchild=NULL;
		}
		rear++;
		Queue[rear]=p;
		if(rear==1){
			bt=p;
		}
		else{
			if(p!=NULL&&Queue[front]!=NULL){
				if(rear%2==0){
					Queue[front]->lchild=p;
				}
				else{
					Queue[front]->rchild=p;
				}
			}
			if(rear%2==1){
				front++;
			}
		}
	}
	return bt;
}

int preOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		printf("%c ",bt->data);
		preOrderTraverse(bt->lchild);
		preOrderTraverse(bt->rchild);
	}
	return 0;
}

int inOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		inOrderTraverse(bt->lchild);
		printf("%c ",bt->data);
		inOrderTraverse(bt->rchild);
	}
	return 0;
}

int postOrderTraverse(struct biTree * bt){
	if(bt!=NULL){
		postOrderTraverse(bt->lchild);
		postOrderTraverse(bt->rchild);
		printf("%c ",bt->data);
	}
	return 0;
}

int levelOrderTraverse(struct biTree * bt){
	struct queue * queue;
	struct biTree * p;
	queue=initQueue();
	if(bt!=NULL){
		p=bt;
		enQueue(queue,p);
		printf("%c ",p->data);
		while(queue->front!=queue->rear){
			p=queue->front->next->elem;
			if(p->lchild!=NULL){
				enQueue(queue,p->lchild);
				printf("%c ",p->lchild->data);
			}
			if(p->rchild!=NULL){
				enQueue(queue,p->rchild);
				printf("%c ",p->rchild->data);
			}
			deQueue(queue);
		}
	}
	return 0;
}

int test(){
	struct biTree * bt;
	bt=(struct biTree *)malloc(sizeof(struct biTree));
	bt=createBiTree(bt);
	preOrderTraverse(bt);
	printf("\n");
	inOrderTraverse(bt);
	printf("\n");
	postOrderTraverse(bt);
	printf("\n");
	levelOrderTraverse(bt);
	printf("\n");
	return 0;
}

int main(){
	test();
	return 0;
}