Korter optellen

<?php
if(isset($_POST['rekenen']))
{
	$getal1 = $_POST['getal1'];
	$getal2 = $_POST['getal2'];
	if($_POST['test'] == "optellen")
	{
		echo $getal1 + $getal2;
	}
	elseif($_POST['test'] == "aftrekken")
	{
		echo $getal1 - $getal2;
	}
	elseif($_POST['test'] == "delen")
	{
		echo $getal1 / $getal2;
	}
	else
	{
		echo $getal1 * $getal2;
	}
}
?>

<?php
if(isset($_POST['rekenen']))
{
	$getal1 = $_POST['getal1'];
	$getal2 = $_POST['getal2'];
	if($_POST['test'] == "optellen")
	{
		echo $getal1 + $getal2;
	}
	elseif($_POST['test'] == "aftrekken")
	{
		echo $getal1 - $getal2;
	}
	elseif($_POST['test'] == "delen")
	{
		echo $getal1 / $getal2;
	}
	else
	{
		echo $getal1 * $getal2;
	}
}
?>

<?php
function calc($getal1, $getal2, $test){
    if($test == "optellen"){
        echo $getal1 + $getal2;
    }
    elseif($test == "aftrekken"){
        echo $getal1 - $getal2;
    }
    elseif($test == "delen"){
        echo $getal1 / $getal2;
    }else{
        echo $getal1 * $getal2;
    }
}
calc("10","5","aftrekken");
echo "<br>";
calc("10","5","optellen");
echo "<br>";
calc("10","5","delen");
?>

<?php
function calc($getal1, $getal2, $test){
    if($test == "optellen"){
        echo $getal1 + $getal2;
    }
    elseif($test == "aftrekken"){
        echo $getal1 - $getal2;
    }
    elseif($test == "delen"){
        echo $getal1 / $getal2;
    }else{
        echo $getal1 * $getal2;
    }
}
calc("10","5","aftrekken");
echo "<br>";
calc("10","5","optellen");
echo "<br>";
calc("10","5","delen");
?>

<?php
function calc($getal1, $getal2, $test){
    if($test == "optellen"){
        echo $getal1 + $getal2;
    }
    elseif($test == "aftrekken"){
        echo $getal1 - $getal2;
    }
    elseif($test == "delen"){
        echo $getal1 / $getal2;
    }else{
        echo $getal1 * $getal2;
    }
}
if($_SERVER['REQUEST_METHOD'] == 'POST'){
	$nr1 = $_POST['nr1'];
	$nr2 = $_POST['nr2'];
	$berekening = $_POST['berekening'];
calc("$nr1","$nr2","$berekening");	
}else{
?>
<form action="<? $_SERVER['PHP_SELF']; ?>" method="post">
<input type="text" name="nr1"> 
<select name="berekening">
	<option value="optellen">optellen</option>
	<option value="aftrekken">aftrekken</option>
	<option value="delen">delen</option>
</select> 
<input type="text" name="nr2"><br>
<input type="submit" value="bereken">
</form>
<?
}
?>

<?php
function calc($getal1, $getal2, $test){
    if($test == "optellen"){
        echo $getal1 + $getal2;
    }
    elseif($test == "aftrekken"){
        echo $getal1 - $getal2;
    }
    elseif($test == "delen"){
        echo $getal1 / $getal2;
    }else{
        echo $getal1 * $getal2;
    }
}
if($_SERVER['REQUEST_METHOD'] == 'POST'){
	$nr1 = $_POST['nr1'];
	$nr2 = $_POST['nr2'];
	$berekening = $_POST['berekening'];
calc("$nr1","$nr2","$berekening");	
}else{
?>
<form action="<? $_SERVER['PHP_SELF']; ?>" method="post">
<input type="text" name="nr1"> 
<select name="berekening">
	<option value="optellen">optellen</option>
	<option value="aftrekken">aftrekken</option>
	<option value="delen">delen</option>
</select> 
<input type="text" name="nr2"><br>
<input type="submit" value="bereken">
</form>
<?
}
?>