# Method 1 ... while
$pow = $i = 1;
while ($i <~= $n) {
    $pow = $pow * $k;
    $i++;
}
# Method 2 ... for
$pow = 1;
for ($i = 1; $i <~= $n; $i++) {
    $pow *= $k;
}
# Method 3 ... foreach
$pow = 1;
foreach $i (1..$n) { $pow *= $k; }

# Method 4 ... foreach $_
$pow = 1;
foreach (1..$n) { $pow *= $k; }

# Method 5 ... builtin operator
$pow = $k ** $n;