CODEWITHSUNDEEP
php
user3263879
user3263879

Reputation:

How to subtract multiple times from a total and show the remainder of each calculation in PHP?

Let's say $total=1000 and I need to subtract $a=100, $b=50, $c=10, $d=50 from $total and show the remainder each time. I would like to see:

$total-$a=$new_total //900
$new_total-$b=$new_total //850
$new_total-$c=$new_total //840
$new_total-$d=$new_total //790

The first line is easy but after that I'm lost. The subtracted numbers are comming from a form so I don't know how many there will be. Could be $a-$t or just $a. Hope this makes sense!

Upvotes: 1

Views: 297

Answers (1)

scrowler
scrowler

Reputation: 24405

Swap your assignment around and echo the result each time:

echo PHP_EOL, $total = 1000;

echo PHP_EOL, $new_total = $total-$a; //900
echo PHP_EOL, $new_total = $new_total-$b; //850
echo PHP_EOL, $new_total = $new_total-$c; //840
echo PHP_EOL, $new_total = $new_total-$d; //790

Example

Sounds like the number of these variables is dynamic. The easiest way to implement something like this with a variable number of inputs is to use an array in the frontend and loop it in the back:

<?php for ($i = 1; $i <= 10; $i++) : ?>
    <input type="text" name="numbers[]" />
<?php endif; ?>

Then:

echo PHP_EOL, $total = 1000;
foreach ($_POST['numbers'] as $number) {
    echo PHP_EOL, $total -= $number;
}

Example

Upvotes: 1

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