function HFC($dividend, $divisor) {
$remainder;
$hcf = 0;
do {
$remainder = $dividend % $divisor;
if ($remainder == 0) {
$hcf = $divisor;
}
else {
$dividend = $divisor;
$divisor = $remainder;
}
} while($remainder != 0);
return $hcf;
}
$dividend = 18;
$divisor = 27;
echo "HCF = " . HFC($dividend, $divisor);
/*
run:
HCF = 9
*/