void list_account(FILE *fp)
{
    int i =0;
    printf("合计%d个账号:\n",cur_account-1);// cur_account减去多加的1
    for(i = 0;i< cur_account-1;i++)
    {
        printf("账户：%d:\n",i+1);
        printf("账号:%d\n",accountcollection[i].account);
        printf("姓名:%s\n",accountcollection[i].name);
        printf("余额:%.2f\n",accountcollection[i].balance);
    }
}
int search_key(FILE *fp,int key,int i)
{
    if (accountcollection[i].key == key)
        return 1;
    else
        return 0;
}