PHP Arithmetic Operators

Question

Hi there

Can anyone explain the output of the following code?
I can't find anything in the manual that refers to +- operators next to each other?

<?php
$sale = 200;
$sale = $sale - + 1;
echo $sale; //Output 199
$sale = $sale + - 1;
echo $sale; //Output 199
?>

Answer 1

I think it's not +- or -+ operator. It works like this :
s = s + (-1)
or, s = s - 1

s = s - (+1)
or, s = s - 1

Thats why if s = 200
both equation returns
s - 1 = 200 - 1 = 199

Answer 2

hope that you are aware of negative number in maths, 200 - +1 means 200 substraction positive 1 that is 199, similarly 200+ -1 means add negative 1 to 200 that will be 199.