sub find_int_in_array
{
    my ( $arref, $targ ) = @_; # args are array ref, int value

    my $asize = scalar @$arref;
    my $lasta = $asize - 1;
    my $result = ( $targ < $$arref[0] or $targ > $$arref[$lasta] ) ? -1 :
                 ( $targ == $$arref[$lasta] ) ? $lasta :
                 ( $targ == $$arref[0] ) ?  0 : undef;

    return $result if ( defined( $result ));

    my $nextidx = $asize / 2;
    my $nextinc = $nextidx / 2;
    while ( ! defined( $result )) {
        if ( $$arref[$nextidx] == $targ ) {
            $result = $nextidx;
        } 
        else {
            my $newidx = ( $$arref[$nextidx] < $targ ) ?
                $nextidx + $nextinc : $nextidx - $nextinc;
            $result = -1 if ( $nextidx == $newidx );
            $nextidx = $newidx;
            $nextinc /= 2;
        }
    }
    return $result;
}