In if condition pass post value with condition operrator - php

Question

I want to post conditional operator from Form Input. And in IF condition use the posted operator. Unable to do so any logic to gt it done.
<form action="" method="post" accept-charset="utf-8">
<input name="postvalue" size="5" maxlength="7" value=">=5">
<p><input type="submit" value="Go"></p>
</form>
<?php
if(10 $_POST["postvalue"]) {
echo "Its greater than 5";
} else {
echo "Its less than 5";
}
?>

Answer 1

You are probably looking for something like this:
<form action="" method="post" accept-charset="utf-8">
<input name="term" size="5" maxlength="7" value=">=5">
<p><input type="submit" value="Go"></p>
</form>
<?php
// separate operator and operand from the posted value
preg_match('/^([=<>!]+)([0-9]+)$/', $_POST['term'], $tokens);
$operator = $tokens[1];
$operand = $tokens[2];
// create an evaluation function
$check = create_function('$value', '
$operand = '.$operand.';
switch("'.$operator.'") {
case "==": return ($value==$operand);
case "!=": return ($value!=$operand);
case "<": return ($value<$operand);
case "<=": return ($value==$operand);
case ">": return ($value>$operand);
case ">=": return ($value>=$operand);
default: throw new Exception("invalid operator");
}');
// apply the evaluation function to some value
try {
if ($check(10)) {
echo "10 is greater than 5";
} else {
echo "10 is less than 5";
}
} catch (Exception $e) {
echo sprintf('Exception: %s', $e->getMessage());
}
?>
Obviously error detection has to be added and the like...
Anyway this is a pretty "strange" architecture... Consider other approaches, since this approach is somewhat prone to failures. Instead you should post operand and operator in separate input fields (post fields) to simplify evaluation and make things more robust. The operator probably should be offered as a select input, the operand as a number spinner...