maxCommonDivisor.php

function calMaxCommonDivisor($m, $n) {
    if ( $m < $n ) {
        $tmp = $m;
        $m = $n;
        $n = $tmp;
    }
    $r = $m % $n;
    while ($r != 0) {
        $m = $n;
        $n = $r;
        $r = $m % $n;
    }

    return $n;
}

if ( $argc != 3 ) {
    exit;
}
$m = $argv[1];
$n = $argv[2];
echo calMaxCommonDivisor($m, $n), "\n";