程序代码：

#include <stdio.h>
#include <stdlib.h>
//二叉树的节点

typedef int Status;
typedef char TElementType;
typedef struct BiTrNode
{
    TElementType data;
    struct BiTrNode *lchild;
    struct BiTrNode *rchild;
}BiTrNode, *BiTree;

//队列的节点
typedef BiTree QElementType;
typedef struct QueueNode
{
    QElementType data;
    struct QueueNode *next;
}QNode;
typedef struct LinkQueue
{
    QNode *front;
    QNode *rear;
}*Queue;

//建立队列的头节点

Queue CreateQueue(void)     //这里总是显示用了未初始化的局部变量“q”，但是我声明了啊
{
    Queue q;
    q->front = (QNode *)malloc(sizeof(QNode));
    q->rear = q->front;
    q->front->next = NULL;
    return q;
}
//入队操作

void Add(Queue Q, QElementType data)
{
    QNode *p = (QNode *)malloc(sizeof(QNode));
    p->data = data;
    p->next = NULL;
    Q->rear->next = p;
    Q->rear = p;
}
//出队操作
QElementType Delete(Queue Q)
{
    QElementType data;
    QNode *temp = Q->front->next;
    data = temp->data;
    Q->front->next = temp->next;
    free(temp);
    return data;

}
//判断队列是否为空
Status IsEmpty(Queue Q)
{
    return Q->front->next == NULL;
}
void CreateBiTree(BiTree *T)  //先序遍历生成二叉树

{
    char c;
    scanf("%c", &c);
    if (c == '#')
    {
        *T = NULL;
        return;
    }
    *T = (BiTree)malloc(sizeof(BiTrNode));
    (*T)->data = c;
    CreateBiTree(&((*T)->lchild));
    CreateBiTree(&((*T)->rchild));
}

void LevelOrderTraversal(BiTree T)
{
    Queue Q;
    if (T == NULL)
    {
        return;
    }
    Q = CreateQueue();
    Add(Q, T);
    while (!IsEmpty(Q))
    {
        T = Delete(Q);
        printf("%c", T->data);
        if (T->lchild)
        {
            Add(Q, T->lchild);
        }
        if (T->rchild)
        {
            Add(Q, T->rchild);
        }
    }
}

int main(void)
{
    BiTree T;
    CreateBiTree(&T);
    LevelOrderTraversal(T);
    return 0;
}