c语言实现二叉树层次遍历（借助队列实现）

//c语言实现二叉树层次遍历（借助队列实现）

#include <stdio.h>
#include <stdlib.h>
 
//二叉链表类型定义
typedef struct btnode
{
char data;
struct btnode *lchild,*rchild;
}bitree,*Bitree;


//链队列类型定义
typedef struct LinkQueueNode
{
bitree *data;
struct LinkQueueNode *next;
}LKQueNode;


typedef struct LKQueue
{
LKQueNode *front,*rear;
}LKQue;


//初始化队列
void InitQueue(LKQue *LQ)
{
LKQueNode *p;
p = (LKQueNode*)malloc(sizeof(LKQueNode));
LQ->front = p;
LQ->rear = p;
LQ->front->next = NULL;
}


//判断队列是否为空
int EmptyQueue(LKQue *LQ)
{
if(LQ->front == LQ->rear)
return 1;
else 
return 0;
}


//入队列
void EnQueue(LKQue *LQ,Bitree x)
{
LKQueNode *p;
p = (LKQueNode*)malloc(sizeof(LKQueNode));
p->data = x;
p->next = NULL;
LQ->rear->next = p;
LQ->rear = p;
}


//出队列
int OutQueue(LKQue *LQ)
{
LKQueNode *s;
if ( EmptyQueue(LQ))
{
exit(0);
return 0;
}
else
{
s = LQ->front->next;
LQ->front->next = s->next;
if(s->next == NULL)
LQ->rear = LQ->front;
free(s);
return 1;
}
}


//取队列首元素
Bitree GetHead(LKQue *LQ)
{
LKQueNode *p;
bitree *q;
if(EmptyQueue(LQ))
return q;
else 
{
p = LQ->front->next;
return p->data;
}
} 


//建二叉树
Bitree Initiate()
{
char ch;
Bitree t;
ch = getchar();    
if(ch == '#') 
t = NULL;
   else
   {
t = (Bitree)malloc(sizeof(bitree));
t->data = ch;
t->lchild = Initiate();
t->rchild = Initiate();
   }
   return t;
}


//访问节点
void Visit(Bitree p)
{
printf("%c",p->data); //输出是char
}


//树的高度
int height(Bitree t)
{
int ld,rd;
if(t == NULL) 
return 0;
else 
{
ld = height(t->lchild);
rd = height(t->rchild);
return 1 + (ld>rd?ld:rd);
}
}
 
//层次遍历 
void LevelOrder(Bitree bt)
{
LKQue Q;
Bitree p;
InitQueue(&Q);
if(bt != NULL)
{
EnQueue(&Q,bt);
while(!EmptyQueue(&Q))
{
p = GetHead(&Q);
OutQueue(&Q);
Visit(p);
if(p->lchild != NULL)  
EnQueue(&Q,p->lchild);
if(p->rchild != NULL)  
EnQueue(&Q,p->rchild);
}
}
}


void main()
{
Bitree T;
printf("\n按先序序列输入结点序列，'#'代表空:");
T=Initiate();


printf("\n二叉树的高度为:%d\n",height(T));


printf("\n层次遍历序列为:");
LevelOrder(T);


printf("\n\n");

}

运行结果：