Calculating expression from variable

[Joonake]

Hello all, I have a problem when I am trying to create calculator with PHP. I have created form that you can use to add numbers and operations to input field, but I just cant figure out how to "calculate" the calculation that is stored in variable.

 

For example:

$expression = "5";
$expression .= "+";
$expression .= "5";

$answer = $expression;

 

This way I get just the "5+5" on $answer, but I would like to get "10". I dont want to write my own function to parse the calculation because I know that it exists, just dont know how this is done. I have tried to use printf but it wont help.

 

Anyone can help me?

[Daniel0]

Why don't you try to search this board? This question has been asked many times.

[Joonake]

Why don't you try to search this board? This question has been asked many times.

 

Tried to search but dont find anything. I just cant find proper keywords for this  :'(

[Alex]

Check out this topic: http://www.phpfreaks.com/forums/index.php/topic,295366.0.html