Simple function in PHP with Calculation

Question

I am making very simple program in PHP . Tryig to addition first ..

But dont know ..

Here is code

<?php 
$a=12;
$b=10;
$c="+";

$res=$a."$c".$b;
echo $res;
?>

it output 12+10 as it is concecate..

$c is anything.

Any idea how to do this

Why do you put $c into quotes like "$c"? Also why do you put the operator into a variable? If you just write it without the string, it should work. — hakre
– hakre, Commented Jun 30, 2012 at 21:46

Luc Franken · Accepted Answer · 2012-06-30 09:44:26Z

5

$c is now a string and not a expression "+" is not equal to +.

So:

$res=$a + $b;

If you would really need your structure you would have to do something evil like using eval() or you could do:

$a=12;
$b=10;
$operator='+';

switch($operator) {
  case '+':
    $res=$a + $b;
    break;
  case '-':
    $res=$a - $b;
    break;
}

answered Jun 30, 2012 at 9:44

Luc Franken

3,0141 gold badge19 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user950276 Over a year ago

No i want to use only $c. not +

lll Over a year ago

@user950276: If you want to learn PHP, learn to use it properly.

ComFreek · Accepted Answer · 2012-06-30 09:45:36Z

2

What do you want to do exactly?

If you have the operator as a string, you could try a switch statement:

<?php 
$a=12;
$b=10;
$c="+";

switch($c) {
  case '+': 
      $res = $a + $b;
      break;

  case '-':
      $res = $a - $b;
      break;
}
var_dump($res);
?>

answered Jun 30, 2012 at 9:45

ComFreek

29.5k18 gold badges107 silver badges157 bronze badges

Comments

Joop Eggen · Accepted Answer · 2012-06-30 09:49:06Z

0

Yes, also PHP has an eval(uate) function:

$res = eval($a . $c . $b);

Be sure that $a, $b and $c do not stem from form input, as eval can delete and so on.

answered Jun 30, 2012 at 9:49

Joop Eggen

110k8 gold badges89 silver badges142 bronze badges

Collectives™ on Stack Overflow

Simple function in PHP with Calculation

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related