1.    说明此函数的基本功能，并描述for语句执行的次数
typedef  struct
{int data[MAXSIZE];
 int length;
}SeqList;
SeqList *L;
SeqList *BB(SeqList *L,int i)
{
    int j;
    if (i<1 || i>=L->length+1)
    {printf("the delete postion is errror!\n");
    return(L);};
    for (j = i; j<=L->length; j++)
        L->data[j] =L->data[j+1];
    L->length--;
    return(L);
}