[RESOLVED] custom operator

imran_rajani

Hi Guys,

I knew that there is some mistake but i tried myself.
Can you please let me know how to handle this?

Mistake in

$result= $_REQUEST["one"] $opt $_REQUEST["two"];

index.php

<HTML>
<HEAD>
<TITLE>Calculator</TITLE>
</HEAD>
<BODY>

<form action="result.php" method="get">
1st Value: <input type="text" name="one" /><br>
<select name="opt" id="opt">
<option>+</option>
<option>-</option>
<option>/</option>
<option>*</option>
</select><br>
2nd Value: <input type="text" name="two" /><br>
<input type="submit">
</form>

</BODY>
</HTML>

result.php

<HTML>
<HEAD>
<TITLE>Result</TITLE>
</HEAD>
<BODY>


<?php 
$opt=$_REQUEST["opt"];
$result= $_REQUEST["one"] $opt $_REQUEST["two"]; //error is in this line
//e.g. 2 (one) *(opt) 2(two)

echo result;
?>
</BODY>

</HTML>

laserlight

You would need to transform your attempted use of an operator to the calling of a function.

imran_rajani

Thanks laserlight,

since i'm very new in php, could you please help me knowing how to do.

Thanks

laserlight

Actually, on second thought I might do it this way:

if (isset($_REQUEST['opt'], $_REQUEST['one'], $_REQUEST['two'])) {
    $result = 'Error: invalid operator';
    switch ($_REQUEST['opt']) {
    case '+':
        $result = $_REQUEST['one'] + $_REQUEST['two'];
        break;
    case '-':
        $result = $_REQUEST['one'] - $_REQUEST['two'];
        break;
    case '*':
        $result = $_REQUEST['one'] * $_REQUEST['two'];
        break;
    case '/':
        $result = $_REQUEST['one'] / $_REQUEST['two'];
        break;
    }
    echo $result;
}

Basically, the PHP interpreter has no way of knowing what your input means, even though '+' and '-' make alot of sense to you. As such, you need to map the input to the operations, and one way of doing that is shown above.

imran_rajani

laserlight,

thanks - this will help me.