#!/usr/athena/bin/perl

use strict;

sub hnext;

# get arguments
my $n = shift;
my $nstop = shift;
my $which = lc (shift);

# defaults
$nstop = $n, $n = 1 if ($nstop == undef);
$nstop = 20 if ($nstop == undef);
$which = 'Both' if !($which =~ /(happy|sad|both)/);

# bounds check
$n = 1 if ($n < 1);
$nstop = 1 if ($nstop < 1);

while ($n <= $nstop) {
    
    my $m = $n;
    my $st = 0;
    
    $m = hnext ($m), $st++ while (($m != 1) && (issad ($m) != 1));
    if ($m == 1) {
	print "$n\t$st\n" if ($which =~ /(happy|both)/);
	print "$n\t$st\t$m\n" if ($which =~ /Both/);
    } else {
	print "$n\t$st\n" if ($which =~ /(sad|both)/);
	print "$n\t$st\t$m\n" if ($which =~ /Both/);
    }

    $n++;

}

exit;

sub issad 
{

    my @sad = (4, 16, 37, 58, 89, 145, 42, 20);
    my $n = shift;
    foreach my $m (@sad) {
	return 1 if ($m == $n);
    }

    return 0;
    
}

sub hnext 
{
    
    my $n = shift;
    my @digits = split (//, $n);
    my $sum = 0;

    foreach my $digit (@digits) {
	$sum = $sum + ($digit * $digit);
    }
    
    return ($sum);

}