PHP - How to exit an if - php

Question

My code is showing an error in the line commented below saying:
ErrorException A non-numeric value encountered
The input variable receives an asterisk character and runs through my if instead of stopping at the first iteration. Could you help me find out the reason for the error or tell me the command to exit if after the first if iteration?
$minute = '*';
$pos1 = strpos($minute, '*');
$pos2 = strpos($minute, ',');
$pos3 = strpos($minute, '-');
$pos4 = strpos($minute, '/');
if (true == $pos1) {
$operator = '*';
} elseif (true == $pos2) {
$operator = ',';
} elseif (true == $pos3) {
$operator = '-';
} elseif (true == $pos4) {
$operator = '/';
} else {
$minute_atual = Carbon::now->format('i');
if ($minute < $minute_current) {
$minute = 60 - ($minute_current - $minute); // The error message says it is on that line
$operator = $ minute;
} elseif ($minute_current == $minute) {
$minute = '0';
$operator = $minute;
} else {
$minute = $minute - $minute_current;
$operator = $minute;
}
}

Answer 1

strpos is notorious for that error.
Indeed
$minute = "*";
$pos1 = strpos($minute, '*');
var_dump($pos1);
// 0 because this is the first (0th) character
so the test true == 0 fails
Use strict inequality $pos0 !== false instead
Function reference : https://www.php.net/manual/en/function.strpos
See the warning in the "return value" section.

Answer 2

$minute = '*';
This is a string. And php can't apply numeric operations over it. I don't see if you are assigning a numeric value to it before the subtraction.
Basically you are trying to do "number - (number - string)". Probably you are missing some part of your logic.
Also you don't need to set priority over the operations if they are subtraction or addition.
60 - $minute_current - $minute
Will give you the same result. Of course if $minute is integer.
And also I strongly recommend to avoid weak comparison, use ===, !== instead. So you know exactly what you are doing