如何在数学计算中使用PHP POST变量？

Question

first time asking on the site so sorry if the question isnt too detailed.

My code:

<?php
  $a = ($_POST['a']);

  $b = ($_POST['b']);

  $op = ($_POST['c']);

  $ans = $a   $op   $b;

  echo $ans;
?>

As you can see I'm passing in numbers $a and $b and want to do something with them depending on the $op which gets passed through.

My problem is that I cant get at the variable $op in the way I want to. Ideally if $op is "+" id like the $ans to be something like 1 + 2.

I'm guessing that I have a problem with syntax.

Many thanks

David

Answer 1

You can use the switch statement:

switch ($op) {
    case '+':
        $ans = $a + $b;
        break;
    case '-':
        $ans = $a - $b;
        break;
    ...
}