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; }