[Resolved] Mathematical Functions

Hi,

Is there any function that can convert + number to - and - to + ?

i.e:
3 will be -3
and
-4 will be 4

Thanks,
Assaf

$x = -$x;

Or in function form ...

function swapsgn($x){ return -$x; }

Then,

$x = swapsgn($x);

hi!
you can easily make such a function by yourself

function plusMinus($number) {
 $number = $number * (-1);
}

Hi LarsLai,

That's not actually going to be much use, I'm afraid ...

With your definition, there is no 'return', so cannot be used to assign ...

$number = 20;

$x = plusMinus($number); // Won't work ... no return in plusMinus()

// And since you haven't passed by reference ...
echo $number;// Still prints 20;

To fix for use with references ...

function plusMinus(&$number) { $number *= -1; }

Then ...

plusMinus($number); // This will work
echo $number;// Now prints -20;

Paul 🙂

Thanks Paul. Right you are, of course.