Calculator in php using buttons

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I am new with PHP and I am making a calculator using buttons and I am having error, I would like to know the reason for the error, so far only did the sum and subtraction part.

<!doctype html>
<html lang="pt-br">

<head>
    <title>Resultado</title>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css"
        integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>

<body>

<?php

  $n1 = $_GET['numero1'];
  $n2 = $_GET['numero2'];
  $op = $_GET['escolha'];

    switch ($escolha){
        case = 'Soma':
            $result = $n1 + $n2;
            echo "O Resultado é: $result"; 
            break;
        case ='Subtração':
            $result = $n1 + $n2;
            echo "O Resultado é: $result"; 
            break; 
        }


?>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
        integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
        crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"
        integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49"
        crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"
        integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy"
        crossorigin="anonymous"></script>
</body>

</html>

Form

<!doctype html>
<html lang="pt-br">

<head>
    <title>Calculado Boladonaaa</title>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css"
        integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>

<body>

    <div class="container">
        <div clas="row">

            <div clas="col-md-6">

                <form id="formulario" name="formulario" method="get"
                                          action="resultado.php">
                    <h3>Calculada</h3>
                    <div class="form-group">
                        <label for="numero1">Digite um número para calculo</label>
                        <input type="number" class="form-control" name="numero1" id="numero1"
                            placeholder="Digite o primeiro número">
                    </div>
                    <div class="form-group">
                        <label for="numero2">Digite o segundo número para o calculo</label>
                        <input type="number" class="form-control" name="numero2" id="numero2"
                            placeholder="Digite o segundo número"><br>
                   </div>
                    <h4>Selecione a operação desejada<h4>        
                    <input class="btn btn-danger" type="submit" name="operacao" value="Soma" id="Soma">
                    <input class="btn btn-primary" type="submit"  name="operacao" value="Subtração" id="Subtração">
                    <input class="btn btn-success" type="submit"   name="operacao" value="Multiplicação" id="Multiplicação">
                    <input class="btn btn-warning" type="submit" name="operacao" value="Divisão" id="Divisão">
                  </form>         
            </div>

        </div>

    </div>








    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
        integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
        crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"
        integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49"
        crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"
        integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy"
        crossorigin="anonymous"></script>
</body>

</html>
php

  • The result page.php is returning not found - 404 Error.

  • And, by the way, what’s the mistake?

  • ( ! ) Parse error: syntax error, Unexpected '=' in C: wamp64 www project_calculated result.php on line 24, in the sum case line.

  • This equal does not exist, see documentation.

3 answers

2

I’m seeing some problems in your code:

$op = $_GET['escolha']; # esta jogando o escolha para a var $op
switch ($escolha) # esta usando $escolha que não existe
# case = 'Soma': # errado
case 'Soma': # correto
# seu switch falta um default:

Applying the changes:

$n1 = isset($_GET['numero1']) ? $_GET['numero1']*1 : 0 ; # verifico se o get foi passado e converto para inteiro fazendo o *1
$n2 = isset($_GET['numero2']) ? $_GET['numero2']*1 : 0 ;
$op = isset($_GET['escolha']) ? $_GET['escolha'] : 0 ;

switch ($op){ # corrigido

    case 'Soma': # corrigido
        $result = $n1 + $n2;
        echo "O Resultado é: $result"; 
        break;

    case 'Subtração': # corrigido
        $result = $n1 - $n2; # corrigido
        echo "O Resultado é: $result"; 
        break; 

    default: # adicionado
        echo "Sem resultado";
}

Editing:

As commented by @Andersoncarloswoss, you can convert to int/float using php functions intval and floatval

# esta linha esta fazendo o mesmo que o if abaixo
$n1 = isset($_GET['numero1']) ? $_GET['numero1']*1 : 0;

#  $var = <checagem> ? <valor caso verdade> : <valor caso falso>;


if( isset($_GET['numero1']) )
{
    $n1 = $_GET['numero1'] * 1;
    # O vezes (*) 1 era para transformar o valor para inteiro 
    # voce pode utilizar intval( $_GET['numero1'] ) para inteiro
    # ou ainda floatval( $_GET['numero1'] ) para float 
    # fiz isso pq o valor esta vindo por GET então acredito que nesse momento ele é string
    # mas aparentemente quando você aplicar a soma ou a subtração ...
    # ele vai tratar como numero como o @AndersonCarlosWoss disse em seu comentário
}
else
{
    $n1 = 0;
}

@Lucas: Thanks really, I made the changes, it worked but now only this adding even when I click subtraction
I think that part might be causing the problem

<input class="btn btn-danger" type="submit" name="operacao" value="Soma" id="Soma">
<input class="btn btn-primary" type="submit"  name="operacao" value="Subtração" id="Subtração">
<input class="btn btn-success" type="submit"   name="operacao" value="Multiplicação" id="Multiplicação">
<input class="btn btn-warning" type="submit" name="operacao" value="Divisão" id="Divisão">

One solution would be to put the type='radio' and create another input to do Submit, something like in the example below.

<label>
    <input type="radio" name="operacao" value="Soma" id="Soma">
    Soma
</label>
<label>
    <input type="radio" name="operacao" value="Subtração" id="Subtração">
    Subtração
</label>
<label>
    <input type="radio" name="operacao" value="Multiplicação" id="Multiplicação">
    Multiplicação
</label>
<label>
    <input type="radio" name="operacao" value="Divisão" id="Divisão">
    Divisão
</label>

<input type='submit' value='Enviar'>
  • 1

    What +$_GET['numero2']*1 ago?

  • My mistake, was to convert to whole, but do not remember if the php accepts the conversion +$var

  • I ended up changing last minute to $var*1

  • 1

    To my mind, wear intval or floatval would be more explicit than multiplying by "a random value", disregarding the fact that PHP already treats strings numbers as numbers, then conversion becomes unnecessary.

  • Thanks even, I made the changes, it worked but now only this adding even when I click subtraction

  • 1

    And I did not understand this "? $_GET['numero1']*1 : 0 ;" which was added next to the variables

  • @Lucasalmeida I made a change in response, check if it meets

Show 2 more comments

1

Instead of case = 'Soma', the right case is 'Soma'

        switch ($variable) {
        case 'value':
            # code...
            break;

        default:
            # code...
            break;
    }

  • Vlw, I’ve already corrected

0

 switch ($escolha){
        case 'Soma':
            $result = $n1 + $n2;
            echo "O Resultado é: $result"; 
            break;
        case 'Subtração':
            $result = $n1 + $n2;
            echo "O Resultado é: $result"; 
            break; 
        }

Your problem is in the case you are using assignment and the syntax is as follows in the above code!

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