checking if a number is divisible by 6 PHP

Question

I want to check if a number is divisible by 6 and if not I need to increase it until it becomes divisible.

how can I do that ?

Answer 1

I see some of the other answers calling the modulo twice.

My preference is not to ask php to do the same thing more than once. For this reason, I cache the remainder.

Other devs may prefer to not generate the extra global variable or have other justifications for using modulo operator twice.

Code: (Demo)

$factor = 6;
for($x = 0; $x < 10; ++$x){  // battery of 10 tests
    $number = rand( 0 , 100 );
    echo "Number: $number Becomes: ";
    if( $remainder = $number % $factor ) {  // if not zero
        $number += $factor - $remainder;  // use cached $remainder instead of calculating again
    }
    echo "$number\n";
}

Possible Output:

Number: 80 Becomes: 84
Number: 57 Becomes: 60
Number: 94 Becomes: 96
Number: 48 Becomes: 48
Number: 80 Becomes: 84
Number: 36 Becomes: 36
Number: 17 Becomes: 18
Number: 41 Becomes: 42
Number: 3 Becomes: 6
Number: 64 Becomes: 66

Answer 2

Use the Mod % (modulus) operator

if ($x % 6 == 0) return 1;


function nearest_multiple_of_6($x) {
    if ($x % 6 == 0) return $x;    

    return (($x / 6) + 1) * 6;
}

Answer 3

if ($variable % 6 == 0) {
    echo 'This number is divisible by 6.';
}:

Make divisible by 6:

$variable += (6 - ($variable % 6)) % 6; // faster than while for large divisors

Answer 4

result = initial number + (6 - initial number % 6)

Answer 5

Assuming $foo is an integer:

$answer = (int) (floor(($foo + 5) / 6) * 6)