how to fix Laravel Error when executing the route

I have following link in blade file for the edit page

<a href="" class="btn btn-default btn-sm">Edit</a>

and my controller is as following

public function edit()
    {
        return view('topic.edit');
    }

and route is

Route::resource('topic','TopicController');

but got following error message Symfony\Component\Debug\Exception\FatalThrowableError syntax error, unexpected ';', expecting ',' or '

how to fix this problem?

via Chebli Mohamed