for (my $i=0;$i<@array;$i++)
{
   $array[$i] = 3; # dummy value
   # do your stuff, $i being the counter
}

##</code><code>##

foreach (0..@array)
{ 
   $array[$_] = 3;
   # do your stuff, $_ being the counter
}

##</code><code>##

foreach(@array)
{
   # use $_ as counter
   # do your stuff
}