Undefined variable of view in laravel 5.4 - php

Question

I define a variable in view. But problem is that it shows undefined. My task is, first i take all the input from user using form helper then i want to post it to the store function & do some calculation and then pass it to the view for showing purpose. But i tried it, unfortunately shows undefined.Undefined variable is "totalamount" Here i attached all the code:
controller:
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\TestSetup;
use Illuminate\Support\Facades\Input;
class TestRequestController extends Controller
{
/**
* Display a listing of the resource.
*
* #return \Illuminate\Http\Response
*/
public function index()
{
//
}
/**
* Show the form for creating a new resource.
*
* #return \Illuminate\Http\Response
*/
public function create()
{
$allTestNames=TestSetup::all()->pluck('test_name','id');
// $testNames=TestSetup::orderBy('test_name')
// ->get();
return view('testrequestentries.createTestRequestEntry')->withAlltestnames($allTestNames);
// return view('testrequestentries.createTestRequestEntry');
}
/**
* Store a newly created resource in storage.
*
* #param \Illuminate\Http\Request $request
* #return \Illuminate\Http\Response
*/
public function store(Request $request)
{
// if(Input::get('Add')) {
$total=$request->fee+$total;
return view('testrequestentries.createTestRequestEntry')->withTotalamount($total);
// }else if(Input::get('Save')){
//
// }
}
/**
* Display the specified resource.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function show($id)
{
//
}
/**
* Show the form for editing the specified resource.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function edit($id)
{
//
}
/**
* Update the specified resource in storage.
*
* #param \Illuminate\Http\Request $request
* #param int $id
* #return \Illuminate\Http\Response
*/
public function update(Request $request, $id)
{
//
}
/**
* Remove the specified resource from storage.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function destroy($id)
{
//
}
}
view
#extends ('main')
#section('title','|Test Request Entry')
#section('stylesheets')
{!! Html:: style('css/parsley.css')!!}
#endsection
#section('content')
{!! Form::open(['route' => 'testrequests.store','data-parsley-validate'=>'']) !!}
{{Form::label('patient_name','Name of the Patient:')}}
{{Form::text('patient_name',null,array('class' => 'form-control','required'=>'', 'data-parsley-required-message' => 'Patient Name is required'))}}
{{Form::label('date_of_birth','Date Of Birth:')}}
{{Form::date('date_of_birth',null,array('class' => 'form-control','data-parsley-required' =>'true')) }}
{{Form::label('mobile_no','Mobile No:')}}
{{Form::text('mobile_no',null,array('class' => 'form-control','type'=> 'number','maxlength'=>'11','minlength' => '11','required'=>'', 'data-parsley-required-message' => 'Mobile No is required'))}}
{{Form::label('test_id','Select Test:')}}
{{Form::select('test_id',$alltestnames,null,['class'=>'form-control','required'=>'','placeholder' => 'Pick a Test...'])}}
{{Form::label('fee','Fee:')}}
{{Form::text('fee',null,array('class' => 'form-control','required'=>'', 'data-parsley-required-message' => 'Fee is required'))}}
{{Form::submit('Add',array('class' => 'btn btn-lg btn-block btn-success','style' => 'margin-top:10px;'))}}
<table class="table table-bordered" style="margin-top: 50px;">
<thead>
<tr>
<th>SL</th>
<th>Test Name</th>
<th>Fee</th>
<th>Type Name</th>
</tr>
</thead>
#php ($i=1)
<tbody>
<tr>
<th scope="row">{{$i}}</th>
<td>{{$totalamount}}</td>
</tr>
</tbody>
#php ($i++)
</table>
{!! Form::close() !!}
#section('scripts')
{!! Html:: script('js/parsley.min.js') !!}
#endsection
#endsection

Answer 1

I bet the view is returned from create() here, so change this:
return view('testrequestentries.createTestRequestEntry')->withAlltestnames($allTestNames);
To:
return view('testrequestentries.createTestRequestEntry', [
'alltestnames' => $allTestNames,
'totalamount' => $total
]);
In the store() method, do not return the view. Redirect back() or to index() or show() methods instead.

Answer 2

first thing first: check the value of $total=$request->fee+$total;
ie: put "dd('$total', $total);" right after the line you set it, before the return.
second: make it simplier return view(...)->with('totalAmount', $total);
test the value of $totalAmount in the view (BLADE file)
ie: {{dump('totalAmount', $totalAmount)}}
Anyway the store() method does NOT store anything ... WHY THAT?