function modulus($a, $b)
{
if (areValidInputs($a, $b)) {
if (isZero($b)) {
return "ERROR: Cannot modulus by zero . Try again. Got {$b}." . PHP_EOL;
}
return $a % $b;
} else {
return errorMessages($a, $b);
}
}
}
if ($_POST) {
validateForm($validationErrors);
}
switch ($operationFromPost) {
case 1:
$result = $firstNumber + $secondNumber;
break;
case 2:
$result = $firstNumber - $secondNumber;
break;
case 3:
$result = $firstNumber * $secondNumber;
break;
case 4:
if (isZero($secondNumber)) {
$result = "Error: division by zero is not allowed!";
} else {
$result = $firstNumber / $secondNumber;
}
break;
}
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Basic Calculator</title>
<link rel="stylesheet" type="text/css" href="reset.css"/>
/**
* Determines whether given string is null or only contains
* '0' (zero) or 'null' characters.
*
* @param string $string_
*
* @return boolean
*/
function isNullOrZero($string_)
{
if ((bool) $string_) {
return isZero($string_);
}
return true;
}
