Undefined variable: in Laravel - php

Question

i can't get variable seat in form action at {!! Form::open(['action' => ['SeatController#book', $seat->id] , 'method' => 'POST'])!!} to working. here is my code:
blade.php:
#extends('layouts.app')
#section('content')
<br><br><br>
<h3>From {{$bus->departdest}} to {{$bus->arrivedest}}</h3>
<div> Date : {{$bus->date}}</div>
<div> Boarding Time : {{$bus->depart}}</div>
<div> Arrival Time : {{$bus->arrival}}</div>
<div> Plate Number : {{$bus->platenum}}</div>
<hr>
<img src="/images/seat.jpg" height="175.5px" width="521.5px" >
<hr>
<div> <h3>Available Seats : {{$bus->available}} </h3></div>
#if ($bus->available>0)
{!! Form::open(['action' => ['SeatController#book', $seat->id] , 'method' => 'POST'])!!}
#csrf
<div class="form-group row">
<label for="num" class="col-sm-4 col-form-label text-md-right">{{ __('Choose seat') }}</label>
<div class="col-md-12">
<select class="form-control{{ $errors->has('num') ? ' is-invalid' : '' }}" name="num">
#foreach($seats as $seat)
#if ($seat->bus_id == $bus->id && $seat->status == 0)
<option value="{{ $seat->id }}">{{ $seat->num }}</option>
#endif
#endforeach
</select>
#if ($errors->has('num'))
<span class="invalid-feedback" role="alert">
<strong>{{ $errors->first('num') }}</strong>
</span>
#endif
</div>
</div>
<br>
{{Form::hidden('_method','POST')}}
{{Form::submit('Confirm', ['class' => 'btn btn-primary'])}}
Cancel
{!! Form::close() !!}
#else
<div> No available ticket </div>
Cancel
#endif
#endsection
BusController.php:
public function show($id){
$bus = Bus::find($id);
$user = Auth::user();
$seats = Seat::all();
return view('showseat')->with(compact('bus', 'user', 'seats'));
}

Answer 1

You might need to book a seat on the Bus? So here:
['SeatController#book', $seat->id]
Should be:
['SeatController#book', $bus->id]
You cannot use $seat there as you are passing $seats to the view, and you iterate to show the seat number in a select element.
Then in your book function you can still get the seat number using
$request->num // or request('num')
As num is the name attribute of your select field for the seat number.