Test if number is odd or even

What is the simplest most basic way to find out if a number/variable is odd or even in PHP? Is it something to do with mod?

I've tried a few scripts but.. google isn't delivering at the moment.

Solution 1:

You were right in thinking mod was a good place to start. Here is an expression which will return true if $number is even, false if odd:

$number % 2 == 0

Works for every integer^PHP value, see as well Arithmetic Operators^PHP.

Example:

$number = 20;
if ($number % 2 == 0) {
  print "It's even";
}

Output:

It's even

Solution 2:

Another option is a simple bit checking.

n & 1

for example:

if ( $num & 1 ) {
  //odd
} else {
  //even
}

Solution 3:

Yes using the mod

$even = ($num % 2 == 0);
$odd = ($num % 2 != 0);