解决instantiateViewController出现的SIGABRT错误

下面代码的功能是显示登录界面，但是调用instantiateViewController时会出现SIGABRT错误，原因是没有设置Storyboard Id。

    func showLoginView(){
        //name为Storyboard的文件名
        let storyboard=UIStoryboard(name: "LoginViewController", bundle: nil)
        //withIdentifier为Storyboard Id
        let loginView=storyboard.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
        present(loginView,animated: true, completion: nil)
    }