tìm ước chung lớn nhất

function ucln($a,$b)
{      $a=abs($a);
$b=abs($b);
if ($a==0 ||$b==0)
return $a+$b;
while ($a !=$b)
{
if($a>$b)
$a=$a-$b;
else
$b=$b-$a;
}
return $a;
}

echo ucln(42,56);

trong C#

static int USCLN(int a, int b)

       {
           a=Math.Abs(a);
           b=Math.Abs(b);
           if (a==0 ||b==0)
               return a+b;
           while (a !=b)
           {
               if(a>b)
                   a=a-b;
               else
                   b=b-a;
           }
           return a;
       }



[caption id="" align="alignnone" width="241" caption="ucnn"][/caption]