#define MaxSize 1000
typedef char ElemType;
typedef struct node
{
    ElemType data;
    struct node *lchild;
    struct node *rchild;
} BTNode;
//创建二叉树
void CreateBTNode(BTNode *&b,char *str)
{
    BTNode *St[MaxSize],*p=NULL;
    int top=-1,k,j=0;
    char ch;
    b=NULL;
    ch=str[j];
    while(ch!='\0')
    {
        switch(ch)
        {
        case '(':top++;St[top]=p;k=1;break;
        case ')':top--;break;
        case ',':k=2;break;
        default:p=(BTNode *)malloc(sizeof(BTNode));
            p->data=ch;p->lchild=p->rchild=NULL;
            if(b==NULL) b=p;
            else
            {
                switch(k)
                {
                case 1:St[top]->lchild=p;break;
                case 2:St[top]->rchild=p;break;
                }   
            }   
        }   
        j++;
        ch=str[j];
    }   
}
//层次遍历算法
void LevelOrder(BTNode *b)
{
    BTNode *p;
    BTNode *qu[MaxSize];
    int front,rear;
    front=rear=-1;
    rear++;
    qu[rear]=b;
    while(front != rear)
    {
        front=(front+1)%MaxSize;
        p=qu[front];
        printf("%c ",p->data);
 
        if(p->lchild!=NULL)
        {
            rear=(rear+1)%MaxSize;
            qu[rear]=p->lchild;
        }
 
        if(p->rchild!=NULL)
        {
            rear=(rear+1)%MaxSize;
            qu[rear]=p->rchild;
        }
    }
}
 
//主函数
int main()
{
    BTNode *b,*h;
    char s[MaxSize] = "A(B(D(,G)),C(E,F))";
 
    CreateBTNode(b,s);
    printf("层次遍历算法的访问次序为：");
    LevelOrder(b);
    printf("\n请输入二叉树括号表示法字符串：\n");
    return 0;
}