checking if a number is divisible by 6 PHP
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 ?
if ($number % 6 != 0) {
$number += 6 - ($number % 6);
}
The modulus operator gives the remainder of the division, so $number % 6 is the amount left over when dividing by 6. This will be faster than doing a loop and continually rechecking.
If decreasing is acceptable then this is even faster:
$number -= $number % 6;
if ($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
$num += (6-$num%6)%6;
no need for a while loop! Modulo (%) returns the remainder of a division. IE 20%6 = 2. 6-2 = 4. 20+4 = 24. 24 is divisible by 6.
So you want the next multiple of 6, is that it?
You can divide your number by 6, then ceil
it, and multiply it again:
$answer = ceil($foo / 6) * 6;
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