#!/usr/bin/perl -w
use strict;

sub display {
    my $ref = shift;
    for my $k (sort keys %$ref){
        print "$k: @{$ref->{$k}}\n";
    }
}

my %hash1;
$hash1{fruit}     = [ qw/apple orange plum/ ];
$hash1{vegetable} = [ qw/leek carrot peas/  ];

display (\%hash1);

for my $k (sort keys %hash1){
    print "$k: @{$hash1{$k}}\n";
}