[code=c]

[/code][code=c]

[/code][code=c]
#include<stdio.h>
#include<stdlib.h>
struct node                                    //树结构体
{
    char data;
    struct node *lchild,*rchild;
};                        
struct line                                    //队结构体
{
    struct node*ch;
    struct line *next;
};                  
struct link                                         //队首，队尾
{
    struct line *front;
    struct line *rear;
    
};                            


void createbitree(struct node*T)                     //建树     
{
    char ch;
    scanf("%c",&ch);
    if(ch==' ')
        T=NULL;
    else
    {
        if(!(T=(struct node*)malloc(sizeof(struct node))))
            exit(0);
        T->data=ch;
        createbitree(T->lchild);
        createbitree(T->rchild);
    }
    
}

    
void initqueue( struct link*q)                              //初始化队  
{
    q->front=q->rear=(struct line*)malloc(sizeof(struct line));
    if(!q->front)
        exit(0);
    q->front->next=NULL;

    
    
}


void enqueue( struct link*q, struct node*e)                      //入队
{
    struct line*p;
    p=(struct line*)malloc(sizeof(struct line));
    p->ch=e;
    p->next=NULL;
    q->rear->next=p;
    q->rear=p;
}
void dequeue(struct link*q,struct node*e)                         //出队
{
    
    char data;
    struct line*p;
    p=q->front->next;
    e=p->ch;
data=e->data;
    q->front->next=p->next;
    if(q->rear==p)
        q->rear=q->front;
    free(q);
    printf("%c ",data);
}


int queueempty(struct link q)                           //判断队是否为空
{
    if(q.front->next==NULL)
        return 1;
    else return 0;
}


void main()
{
 struct link*q;
struct node*p;
 truct node*T;
 createbitree(T);
 initqueue(q);
 p=T;
enqueue(q,p);
while(queueempty(*q)!=1)
{
dequeue(q,p);
if(p->lchild!=NULL)
enqueue(q,p->lchild);
if(p->rchild!=NULL)
enqueue(q,p->rchild);
}
printf("\n");

 printf("按层次遍历树中结点其输出顺序为: \n");
 
}