laravel "Undefined variable: categories "

Question

I am trying to display my categories in the welcome.blade.php, however it gives me an error.

My welcome.blade.php:

<div class="links">
    @foreach($categories as $category)
        <a href="{{ url('/receitas/'.$category->id)}}">{{ $category->name }}</a>
    @endforeach
</div>

My WelcomeController.php:

<?php

    namespace App\Http\Controllers;
    use App\Category;
    use Illuminate\Http\Request;
    use App\Welcome;

class WelcomeController extends Controller
{

    public function index()
    {
        return view('welcome');
    }

    public function show()
    {
    $categories = Category::all();

    return view('welcome', compact([ 'categories' => $categories]));
    }
}

And my web.php:

<?php

Route::get('/', 'WelcomeController@index')->name('entrada');

Route::get('/teste/teste', 'UserController@index');

Auth::routes();

Route::get('/home', 'HomeController@index')->name('home');

Route::get('/receitas', 'ReceitasController@index')->name('receitas');

Route::get('/clientes', 'HomeController@clientes');

Route::get('/category', 'CategoryController@index');

I have already tried to use a @if condition to verify if the variable $categories is empty and it seem it is.

<div class="links">
                @if(empty($categories))
                    Alert: the variable is empty!!
                @else
                    @foreach($categories as $category)
                        <a href="{{ url('/receitas/'.$category->id)}}">{{ $category->name }}</a>
                    @endforeach
                @endif
            </div>

However in my database I have records of categories.

Printscreen of my category table

Can you help me please!