use strict;
use warnings;

# you can initialize this any way you wish, this is proof of concept.
my @source = ( 5, 53, 24, 38 );

my $maxseen = 0;
my $seen_at = 0;
my $cntr = 0;
for ( @source ) {
    if ( $_ > $maxseen ) {
        $maxseen = $_;
        $seen_at = $cntr;
    }
    ++$cntr;
}