What is the best solution for filling limited variables in PHP

Question

Let's say I have 3 variables

$a;
$b;

$c = 30;

What I wish to do here is that I have to divide $c and put it in the first 2 variables which can be easily done by doing.

$a = $c / 2;
$b = $c / 2;

However what if in $b there is a maximum value limit of 10 and $a is limitless.
In this case the values have to be.

$a = 20;
$b = 10;

What would be the best solution for this?

Answer 1

If B has a limit, then you would need to calculate B first. Then work out the difference between C & B and set A as the answer.

<?php

$a;
$b;

$c = 100;


$b = min(10, $c / 2);
$a = ($c - $b);

echo "A: " . $a;
echo "B: " . $b;
?>