#! perl -slw
use strict;

sub minMaxAve {
    die 'Empty list' unless @_;
    my( $min, $max, $sum );
    for( @_ ) {
        die 'Non-numeric value(s)' unless /^[\de+.-]+$/;
        $min = $_ if !defined $min or $min > $_;
        $max = $_ if !defined $max or $max < $_;
        $sum += $_;
    }
    return $min, $max, $sum / @_;
}

for (
    [],
    [ 1 .. 4 ],
    [ 5 , 1, 5, 6, 5 ],
    [ 1, 2, -0.1, 1e-5, 2e10 ],
    [ 'fox', 'dog' ]
) {
    my @results = eval{ minMaxAve @$_ } or warn "[ @$_ ] : $@\n\n" and next;

    printf "[ %s ]\nmin: %g max: %g ave: %g\n\n", join( ', ',@$_ ), @results;
}

__END__
P:\test>junk2
[  ] : Empty list at P:\test\junk2.pl line 5.


[ 1, 2, 3, 4 ]
min: 1 max: 4 ave: 2.5

[ 5, 1, 5, 6, 5 ]
min: 1 max: 6 ave: 4.4

[ 1, 2, -0.1, 1e-005, 20000000000 ]
min: -0.1 max: 2e+010 ave: 4e+009

[ fox dog ] : Non-numeric value(s) at P:\test\junk2.pl line 8.